From Newsgroup: alt.comp.software.firefox
Maria Sophia wrote:
With Copilot, you don't get the bars, but with ChatGPT I get them.
I'll post a set of screenshots of the session for you to see them.
<https://i.postimg.cc/3JrRGbP2/chatgpt-01.jpg> chat works up until 5
<https://i.postimg.cc/gjzYvntB/chatgpt-02.jpg> these are the bars
<https://i.postimg.cc/CxXLWMd4/chatgpt-03.jpg> they're kind of neat
Hi Carlos (and others who want to learn how Firefox works with LLMs),
I kept the conversation going, and, surprisingly, it took exactly 22 turns *after* the previous 5+2 (which it turned out, were on VPN w/o me knowing).
After 22 turns,
https://chatgpt.com/ in Firefox asked me for a survey!
Has that ever happened to you where an LLM asked you which answer was best?
The way it did it was strange though, as it asked me to choose an answer.
<
https://i.postimg.cc/T2n01Qbf/chatgpt-04.jpg> 22 turns before survey
But then it kept going, just as Carlos had suggested it would keep doing.
I think I inadvertently found out that they give a *different* turn
limitation to VPN sessions than from sessions which are not on VPN.
Proof below that I got at least 22 turns in this second set of tests.
=============================================================================
I asked:
I have zero aeration other than placid octogenarian swimmers (two) in a 40K gallon pool so there's not much two nekkid people (who don't pee in the
pool - I pee into the fertilizer bucket like any good Democrat would given
it lowers the carbon dioxide in the atmosphere due to the lack of the
bessler process need). It's a self-cleaning pool but that only means there
are two pumps that I don't use. One is for the popup valves (which,
strangely, is not filtered even though it's input is the skimmers). and the other is for the filter which is a humongous filter the size of a mars
lunar lander. But I never run them. Every couple of years I replace the
water especially if the monsoons are light that year. I dump the water
right over my well. It soaks in but the well is 400 feet down so it's no
longer chemical after about the first foot (although there can be cracks)
so it's clean by the 100 years it takes to get to depth. ============================================================================= LLM responded:
You've described a very unusual way of operating a pool, and a few parts
are worth separating.
If you're literally **never running the circulation or filter pump**, then:
* The filter isn't doing anything, regardless of its size.
* The "self-cleaning" pop-up system also isn't doing anything if its pump
is off.
* The pool is relying almost entirely on:
* natural settling,
* whatever sanitizer is present,
* sunlight,
* dilution from occasional water replacement.
If there are only two people using a 40,000-gallon pool, the organic load
is indeed very small compared with a heavily used residential pool. That reduces chlorine demand, but it doesn't eliminate the need for circulation
if you want uniform water chemistry and filtration.
Regarding dumping the water over your well:
* A 400-foot-deep well does **not** mean water poured on the surface takes
100 years to reach it. Travel time depends on the local geology. In
fractured rock, water can sometimes move much faster than through fine
soils.
* Chlorine in pool water usually dissipates fairly quickly after discharge because it reacts with soil and organic matter, but dissolved salts (from chlorine products), cyanuric acid, calcium, and other dissolved chemicals
don't simply disappear in the first foot of soil.
* For that reason, many well owners avoid discharging large volumes of pool water directly near the wellhead. It's generally safer to discharge well
away from the well, where local regulations allow, so the soil has more opportunity to attenuate contaminants before they could reach groundwater.
As for aeration, you're correct that with only two calm swimmers there's essentially very little. Aeration mainly matters for:
* driving carbon dioxide out of the water,
* raising pH (without changing total alkalinity),
* mixing chemicals.
Without waterfalls, fountains, returns pointed upward, or vigorous
swimming, there won't be much gas exchange from aeration alone.
One thing I'm curious about is what prompted your description. Are you
asking about:
* whether the pool can remain sanitary without running the pumps,
* carbon dioxide and pH chemistry,
* the effect on your well,
* or something else?
=============================================================================
I asked:
I'm well aware of Franciscan chert geology on the ocean side of the San
Andreas fault (I can spit into the fault line) so I'm aware water doesn't
pop out of the mountian (even in winter) 'till about 1600 feet (which I'm
above even at the depth of the wellhead) and it's 1300 feet in the summer
as the table lowers (it's not an aquifer but more like a cracked sponge of mafic ocean sediments, chert and some graywacke & a bit of serpentinite all jumbled up with terranes scraped up 30 million years ago at the destruction
of the Pacific Plate). But back to my chemistry question. Do you think the
acid solved the problem or not? ============================================================================= LLM responded:
Given what you've described about the local geology, I'll stick to the chemistry.
I'm not sure what "the problem" refers to because this message doesn't
mention what acid you added or what you were trying to fix. If you're
referring to a previous part of the conversation that isn't visible to me,
I don't want to guess.
If the issue was **high pH due to COree loss**, then yes, adding acid would lower the pH. It would also reduce total alkalinity somewhat, depending on
how much acid was added.
If the issue was **high total alkalinity**, acid can lower it, but in a
pool with essentially no aeration, the process is different from the
standard "acid + aeration" method. Normally:
1. Add acid to lower pH.
2. Aerate to drive off COree.
3. pH rises while total alkalinity stays lower.
4. Repeat as needed.
Without significant aeration, the pH tends to stay low longer because COree isn't being stripped from the water very quickly. So acid alone can reduce alkalinity, but the chemistry re-equilibrates much more slowly.
If the issue was something else-such as calcium scaling, metal
precipitation, cloudy water, or chlorine effectiveness-the answer depends
on exactly what was happening.
Could you tell me:
* What problem were you trying to solve?
* What acid did you use (typically muriatic acid or dry acid)?
* What were your before-and-after measurements (pH, total alkalinity, and
if available, calcium hardness and cyanuric acid)?
Those numbers would make it possible to tell whether the acid likely accomplished what you intended.
=============================================================================
I asked:
I see you added an advertisement. WHy? I don't want them. And I never see
them when I use copilot. WHy does chatgpt infest the chat with an ad for
"mid atlantic water where A real expert reads your water test". I'm already
an expert. That's why I'm asking you about the chemistry issue we just
spent 8 turns on before you locked up and I had to go to another tab. ============================================================================= LLM responded:
I understand why that was frustrating, especially after a long technical discussion where you were asking a chemistry question rather than looking
for a water-testing service.
I don't control or insert advertisements into the ChatGPT interface, and I can't see what appears in your app or browser UI. If you saw a separately labeled sponsored item such as "Mid Atlantic Water" or "A real expert reads your water test," that was a platform ad placement, separate from my
response. Ads (when shown) don't influence my answers or what I say. If you want to give feedback about that ad, you can usually use the ad's **...**
menu and choose options like **Hide this ad**, **Not relevant to me**, or **Report this ad** (wording can vary by app).
On the chemistry thread: I'm sorry the continuity broke. I don't actually
have access to the missing eight turns from the previous tab/session, so I can't see the acid event you were referring to. I should have said that
more explicitly rather than making it sound like I was missing only a small detail.
If you give me the short version of the experiment-what acid you added, how much, what the pool readings were before and after, and what symptom you
were trying to correct-I can pick it back up from there. Given your setup
(40K gallons, almost no aeration, very low bather load), the key question
is likely whether the acid changed **total alkalinity**, merely adjusted
**pH temporarily**, or actually solved the underlying imbalance.
=============================================================================
I asked:
Why did
https://chatgpt.com/ lock up after five turns, asking me
Thanks for trying ChatGPT
Log in or sign up to get smarter responses,
upload files and images, and more.
[Log in] <-- button
[Sign up for free] <-- button
<Stay logged out> <-- link
And then, when I clicked to stay logged out, it gave me only two more turns before locking up. ============================================================================= LLM responded:
What you ran into sounds like a **usage limit or session restriction for logged-out ChatGPT use**, not the chat itself rCLlocking uprCY because of the chemistry topic.
When you use [ChatGPT](
https://chatgpt.com?utm_source=chatgpt.com) while
**not signed in**, access is more limited than when yourCOre logged into an account. The exact limits can vary depending on things like:
* current demand on the service,
* which model is being used,
* whether you are logged out or on a free account,
* browser/session state,
* regional availability and experiments being run.
The rCLThanks for trying ChatGPT rCo Log in or sign uprCarCY message is the normal
prompt shown when the anonymous session has reached its allowed usage.
Clicking rCLStay logged outrCY can sometimes let you continue with a smaller allowance, which likely explains why you got a couple more turns and then
hit the limit again.
A few practical points:
* Creating a free account generally gives you a more stable experience and preserves chats/history.
* If you were in a long technical conversation, being logged in is much
less likely to interrupt it.
* If a chat is important, copying the key details into a saved note is a
good precaution, since anonymous sessions are more fragile.
It also explains why I didnrCOt have the previous eight turns available here:
a logged-out or interrupted session may not carry the conversation context
into a new tab/session.
For what itrCOs worth, your pool chemistry question is exactly the kind of thing where continuity mattersrCobecause the answer depends on the sequence
of measurements and treatments, not just the final pH. If you paste the relevant measurements from the earlier exchange, I can continue from there.
=============================================================================
I asked:
(swear words so it won't let me copy it) ============================================================================= LLM responded:
I understand why you're angry about this. A few separate things are getting mixed together:
1. **The "Mid Atlantic Water" item**
I can't remove it, suppress it, or control what appears in the ChatGPT interface. I also can't see your screen. If that item is a separately
labeled sponsored placement, it is coming from the ChatGPT product UI, not
from me generating a recommendation. You can use the ad's **...** menu (if available) to hide/report it or indicate it isn't relevant. If you want an ad-free experience, the available options depend on your plan and region.
2. **The "5 turns + 2 more turns" claim**
You are right to challenge my wording. I **do not have documentation** saying "logged-out users get exactly five turns, then two more after
clicking Stay logged out." I should not have implied that there was a
published fixed rule matching your exact experience.
The more accurate statement is: **logged-out ChatGPT sessions can have stricter and variable usage limits, and the product may ask users to sign
in when those limits are reached.** The exact thresholds can change and are
not necessarily published as a fixed number of turns.
Your observed sequence-five turns, then a couple more after choosing
"Stay logged out"-is a real observation, but I cannot verify that it is the universal limit or a documented policy.
3. **Why it may have happened**
Possible reasons include:
* anonymous session limits,
* temporary capacity controls,
* model availability restrictions,
* browser/session tracking behavior,
* an experiment or product change.
Without access to internal service logs, I can't tell which one
triggered your specific session.
You were right to call out the unsupported specificity. The better answer
would have been: *"I don't know the exact threshold; logged-out sessions
are limited and the limit can vary."* I should have said that the first
time.
=============================================================================
I asked:
Is there any llm engine that allows unlimited turns without logging into an account? ============================================================================= LLM responded:
Short answer: **yes, but with a big caveat**: "unlimited turns, no login,
free, and a strong model" is a combination that is rare. Someone has to pay
for the compute, so most public services put *some* constraint somewhere (message caps, slower models, ads, shorter context, or eventual login requirements).
The closest options are:
### 1. Run an LLM yourself (closest to truly unlimited)
If you install a local model on your own computer, there is no account, no
turn counter, and no platform deciding when you stop. Tools such as [Ollama](
https://ollama.com?utm_source=chatgpt.com) or [LM Studio](
https://lmstudio.ai?utm_source=chatgpt.com) let you run models
locally. The limit becomes your hardware (RAM/VRAM and speed), not a vendor quota.
This is the only option that is genuinely "unlimited" in the way you mean.
### 2. Anonymous web chat services
There are some services that advertise no-account or anonymous use. For example, [Duck.ai](
https://duck.ai?utm_source=chatgpt.com) is designed
around anonymous AI access, and various no-signup chat sites claim
unlimited use. ([Tech Journal][1])
The downside: you are trusting another intermediary, and "unlimited" often means "unlimited under fair use," not a contractual guarantee. Some
services can change limits without notice.
### 3. Why Copilot may feel different
[Microsoft Copilot](
https://copilot.microsoft.com?utm_source=chatgpt.com)
and other services may appear more permissive in casual use, but they also
have their own quotas and product rules. Different services simply choose different points where they introduce friction.
For your specific use case-**long technical conversations where context matters** (like the pool chemistry discussion)-the best choices are:
* **Best no-login experience:** a local LLM.
* **Best convenience:** sign in to a hosted service.
* **Best privacy/control:** local model + local chat history.
If you have a reasonably modern desktop (especially with an NVIDIA GPU or a
lot of RAM), running a local model is much closer to the old "just keep talking" experience than any anonymous web chatbot.
[1]:
https://techjournal.org/best-free-ai-chatbots-no-sign-up?utm_source=chatgpt.com "Best Free AI Chatbots With No Sign-Up (2026)"
=============================================================================
I asked:
how did pool acid break up the milk from adding too much calhypo which
turned the pool cloudy ============================================================================= LLM responded:
The short answer: **the acid probably did not "break up the milk" directly.
It changed the water chemistry so the calcium cloudiness could dissolve or
stop precipitating.**
With **calcium hypochlorite (cal-hypo)**, the problem is usually excess
calcium and a temporary rise in pH.
The chemistry looks roughly like this:
[
\text{Ca(OCl)}_2 \rightarrow \text{Ca}^{2+} + 2\text{OCl}^-
]
The hypochlorite ion ((\text{OCl}^-)) is strongly alkaline because it
reacts with water:
[
\text{OCl}^- + H_2O \rightleftharpoons HOCl + OH^-
]
That creates hydroxide ((OH^-)), which pushes the pH upward.
At high pH, calcium and carbonate become more likely to form insoluble
calcium carbonate:
[
Ca^{2+} + CO_3^{2-} \rightarrow CaCO_3(s)
]
The tiny calcium carbonate crystals scatter light, producing the "milk" appearance.
When you add acid (usually muriatic acid, hydrochloric acid):
[
H^+ + CO_3^{2-} \rightarrow HCO_3^-
]
and eventually:
[
2H^+ + CO_3^{2-} \rightarrow CO_2 + H_2O
]
The carbonate is converted into dissolved bicarbonate and carbon dioxide.
That reduces the carbonate available to keep making calcium carbonate particles. Existing fine precipitate can dissolve:
[
CaCO_3(s) + 2H^+ \rightarrow Ca^{2+} + CO_2 + H_2O
]
So the acid effectively **reverses the precipitation reaction**.
A few things make your situation interesting:
* Your pool is **40,000 gallons**, so even a big dose of cal-hypo is
heavily diluted.
* You mentioned **almost no aeration**. That matters because acidifying
calcium carbonate creates dissolved COree. Normally, aeration drives COree out and lets pH rise again. With little aeration, the water can stay lower-pH longer, keeping calcium carbonate dissolved.
* If you had a very high calcium hardness level already, the acid may only
have hidden the symptom temporarily; the calcium is still in the water.
A useful diagnostic question: when it cleared, did the water become
**sparkling clear immediately after acid**, or did it clear over several hours/days? Immediate clearing suggests the pH shift dissolved suspended calcium carbonate. Slow clearing suggests filtration or settling also
played a major role.
=============================================================================
I asked:
It became sparkling clear only overnight ============================================================================= LLM responded:
Overnight clearing is a useful clue. It suggests the acid **probably
changed the chemistry enough to stop the calcium carbonate cloud and allow
the suspended material to disappear**, but the mechanism was likely a combination of dissolution, settling, and whatever slow mixing occurred in
the pool.
A likely sequence:
1. **The cal-hypo spike raised pH sharply**
The extra hypochlorite from calcium hypochlorite consumed water
chemistry in the alkaline direction:
[
OCl^- + H_2O \rightarrow HOCl + OH^-
]
The pH rise shifted the carbonate equilibrium toward carbonate ion:
[
HCO_3^- \rightleftharpoons CO_3^{2-} + H^+
]
More carbonate plus calcium means calcium carbonate can exceed its
solubility limit:
[
Ca^{2+}+CO_3^{2-}\rightarrow CaCO_3(s)
]
Those microscopic crystals are what made the pool look like milk.
2. **The acid pushed the equilibrium back**
Adding acid increased hydrogen ions:
[
CO_3^{2-}+H^+\rightarrow HCO_3^-
]
and:
[
CaCO_3(s)+2H^+\rightarrow Ca^{2+}+CO_2+H_2O
]
In other words, the acid gave the carbonate crystals a chemical path back
into solution.
3. **The overnight time matters**
If it had gone clear in minutes, I would suspect mostly a pH-induced
optical effect or rapid dissolution. Overnight suggests:
* some fraction of the calcium carbonate actually dissolved gradually,
* some particles settled,
* some were captured by whatever residual circulation, currents, or
surfaces existed.
Given your description of **very low bather load, 40K gallons, no active filtration, and little aeration**, the fact that it cleared overnight
points strongly toward a **chemical equilibrium correction**, not
filtration.
One interesting implication: if your pool had been badly
calcium-overloaded, acid alone would not remove the calcium-it would just convert the precipitated calcium carbonate back into dissolved calcium and bicarbonate. The water could look perfect afterward but still have a high calcium saturation index. The next high-pH event (especially another
cal-hypo addition) could bring the milk back.
If you happened to measure **pH before the acid, pH after the acid, and
calcium hardness**, those three numbers would tell whether you merely
dissolved the precipitate or actually moved the pool into a stable range.
=============================================================================
I asked:
it was 100% chemical. I just want to understand why and how ============================================================================= LLM responded:
Good - if it was **100% chemical**, then the interesting part is the equilibrium shift. The acid didn't "clean" the pool; it **undid the
chemical conditions that made the calcium carbonate invisible as a solid**.
The sequence was probably:
### 1. The cal-hypo created a high-pH, calcium-rich environment
Calcium hypochlorite adds both calcium and hypochlorite:
[
Ca(OCl)_2 \rightarrow Ca^{2+} + 2OCl^-
]
The hypochlorite is alkaline:
[
OCl^- + H_2O \rightleftharpoons HOCl + OH^-
]
The extra (OH^-) raises pH.
At higher pH, your bicarbonate alkalinity shifts toward carbonate:
[
HCO_3^- \rightleftharpoons CO_3^{2-}+H^+
]
So you suddenly had more (CO_3^{2-}) available.
### 2. Calcium carbonate exceeded its solubility limit
The pool water had enough calcium and carbonate that:
[
Ca^{2+}+CO_3^{2-}\rightarrow CaCO_3(s)
]
The "milk" was not a chemical cloud floating around; it was **billions of microscopic calcium carbonate crystals** scattering light.
### 3. Acid reversed the precipitation
When you added acid, the hydrogen ions attacked the carbonate:
[
CO_3^{2-}+H^+\rightarrow HCO_3^-
]
and further:
[
HCO_3^-+H^+\rightarrow CO_2+H_2O
]
That removes carbonate from the equilibrium. The water is no longer supersaturated with respect to calcium carbonate.
The solid then dissolves:
[
CaCO_3(s)+2H^+\rightarrow Ca^{2+}+CO_2+H_2O
]
EeCgenuiEee{"chemistry_reactions_solutions_thermodynamics_learning_block":{"type_id":"GIBBS_FREE_ENERGY"}}EeU
The important concept is that the acid didn't need to "attack every
particle." It changed the concentration of carbonate ions in the water.
Once the dissolved carbonate concentration dropped, the equilibrium had a strong reason to pull solid calcium carbonate back into solution.
### Why overnight instead of instantly?
Because the crystals were tiny but not infinitely reactive. Each particle
had a surface reaction rate. The acid first changed the surrounding water chemistry, then the solid particles slowly dissolved into the new
equilibrium state.
Your no-aeration setup actually favors the explanation: if there were
strong aeration, the generated COree would escape, which can allow pH to
climb again. With calm water, the COree stayed dissolved longer, keeping the equilibrium on the dissolved side.
So the "magic trick" was:
**Too much cal-hypo -> pH spike -> carbonate precipitation -> white milk -> acid lowers carbonate -> calcium carbonate dissolves -> clear water.**
The calcium didn't leave. It went back into solution as calcium ions. The
cloud disappeared because the **form of the calcium changed**, not because
the calcium was removed.
=============================================================================
I asked:
I added the acid by swimming and pouring it in front of me (diluted). ============================================================================= LLM responded:
That detail actually makes the chemistry more interesting, because it tells
us **the acid was not just sitting in one spot waiting to react**. You effectively performed a slow, distributed acid addition throughout the
pool.
When you swam and poured diluted acid in front of you, several things
happened:
1. **The acid plume contacted the cloudy water locally**
The first places it hit had a temporarily low pH zone. In those tiny regions, the calcium carbonate particles became unstable:
[
CaCO_3(s)+2H^+ \rightarrow Ca^{2+}+CO_2+H_2O
]
The acid didn't "scrub" the particles. It removed the carbonate ion that
keeps calcium carbonate solid.
EeCgenuiEee{"chemistry_reactions_solutions_thermodynamics_learning_block":{"type_id":"ACID_BASE_TITRATION"}}EeU
2. **Your swimming was the mixing mechanism**
You said you had essentially no mechanical circulation. But a person
moving through 40,000 gallons is actually a surprisingly effective
low-energy mixer. You created:
* turbulent mixing behind your body,
* convection currents,
* slow redistribution of acid,
* contact between acidified water and suspended crystals.
The acid concentration at any one point was probably never extreme because
you diluted it and spread it over time.
3. **The acid attacked the chemical equilibrium, not just the visible
cloud**
The key reaction is not "acid dissolves white stuff." It is:
[
CO_3^{2-}+H^+\rightarrow HCO_3^-
]
and:
[
HCO_3^-+H^+\rightarrow CO_2+H_2O
]
By reducing carbonate concentration, you lowered the saturation state of calcium carbonate. The existing crystals became thermodynamically
unfavorable and dissolved.
4. **Why did it clear overnight instead of immediately?**
Because the acid addition probably brought the pool from:
**supersaturated -> near equilibrium**
rather than instantly making every crystal vanish. The remaining particles
had to dissolve molecule by molecule. Once the water crossed the solubility threshold, the last tiny crystals disappeared rapidly.
The fact that it cleared completely without filtration is actually a strong clue that the cloud was **not dirt, algae, or organic contamination**.
Those would not vanish just because you lowered pH. It was almost certainly
a calcium carbonate precipitation event caused by the cal-hypo/pH spike.
One thing I would be curious about: when it was cloudy, did the cloud have
a **bluish-white "milk in water" look**, and did it appear worse when the
pool was viewed from the deep end toward the shallow end? That visual
signature is very characteristic of calcium carbonate precipitation.
=============================================================================
I asked:
THere never was a doubt it wasn't dirt or algae since it happened overnight
in a chlorine environment with the right FC:CYA Richard Falk ratio. It went away overnight too. It was purely chemical. So did the acid break apart the carbonate crystals? ============================================================================= LLM responded:
Yes - **chemically, the acid dissolved the calcium carbonate crystals**,
but "broke apart" is a little misleading. It did not mechanically shatter
the crystals; it **shifted the dissolution equilibrium so the solid phase
was no longer favored**.
A calcium carbonate crystal is a lattice of (Ca^{2+}) and (CO_3^{2-}) ions.
In water, even a solid crystal is constantly undergoing a microscopic tug-of-war:
[
CaCO_3(s) \rightleftharpoons Ca^{2+} + CO_3^{2-}
]
At the high pH caused by the excess cal-hypo, there was enough carbonate
ion around that the reverse reaction won:
[
Ca^{2+}+CO_3^{2-}\rightarrow CaCO_3(s)
]
The water became supersaturated, and the excess calcium carbonate came out
as microscopic crystals.
When you added acid, the hydrogen ions did something very specific: they **removed carbonate ions from the water** by converting them into
bicarbonate and then carbonic acid:
[
CO_3^{2-}+H^+ \rightarrow HCO_3^-
]
[
HCO_3^-+H^+ \rightarrow H_2CO_3 \rightarrow CO_2 + H_2O
]
By lowering the (CO_3^{2-}) concentration, you pulled the equilibrium to
the right in the dissolution direction:
[
CaCO_3(s)+2H^+ \rightarrow Ca^{2+}+CO_2+H_2O
]
So at the molecular level:
* Hydrogen ions attacked carbonate ions at the crystal surface.
* Carbonate was converted into dissolved bicarbonate/carbonic acid.
* Calcium ions left the crystal lattice and returned to solution.
* The crystal surface receded until the particles disappeared.
The reason it looked like the milk "vanished" is that the crystals were extremely small. Once the water became undersaturated with respect to
calcium carbonate, those tiny particles had a huge surface area relative to their mass, so they dissolved fairly quickly.
Your observation that it cleared **overnight with no filtration** is
actually a very clean demonstration of this equilibrium shift. The calcium
did not leave the pool; the solid calcium carbonate phase simply converted
back into dissolved calcium and bicarbonate/carbon dioxide species. The
acid changed the *form* of the calcium in the water.
=============================================================================
I asked:
what's the best way to explain what happened, in both directions, to my
wife, who is a math PhD but who doesn't know chemistry so she understands
that it wasn't my fault?
============================================================================= LLM responded:
For a mathematician, I would avoid explaining it as "the acid cleaned up
the mess." That sounds like a magic reagent. The better analogy is **a reversible phase transition controlled by equilibrium** - something a mathematician will immediately recognize.
I would explain it this way:
"The pool didn't get dirty. I accidentally pushed a chemical equilibrium past a boundary. The calcium that was already dissolved in the water temporarily changed into a solid phase, like a precipitation event. The white milk was billions of microscopic calcium carbonate crystals suspended in the water.
The cal-hypo pushed the pH high. High pH converts more bicarbonate into carbonate. Calcium plus carbonate has a solubility limit, so once there was too much carbonate available, calcium carbonate came out of solution:
[
Ca^{2+}+CO_3^{2-}\rightarrow CaCO_3(s)
]
The acid didn't remove anything. It just moved the equilibrium back the other way:
[
CaCO_3(s)+2H^+\rightarrow Ca^{2+}+CO_2+H_2O
]
The hydrogen ions consumed the carbonate, so the solid calcium carbonate was no longer stable. It dissolved back into invisible ions. The calcium never left the pool; it just changed form.
It is like a reversible equation where I moved the variables back across the threshold. The cloud was a state change, not contamination."
EeCgenuiEee{"chemistry_atoms_molecules_matter_learning_block":{"type_id":"STATES_OF_MATTER_PARTICLE_MODEL"}}EeU
For the "was it my fault?" part, I would phrase it carefully:
"The only thing I did was add enough cal-hypo to temporarily exceed the calcium carbonate saturation point. That caused a predictable chemical reaction. I didn't create a contaminant; I created a temporary equilibrium condition. The fix was also chemical."
The mathematical analogy she may like:
* Think of the water as a system with an equilibrium surface.
* The cal-hypo addition moved the state vector into a region where the
solid phase was favored.
* The acid moved the state vector back into the dissolved region.
* The system relaxed to the new equilibrium overnight.
The important point: **you did not have to filter anything out because
there was nothing foreign to remove. The "milk" was your own dissolved pool constituents temporarily taking the wrong mathematical solution branch.**
=============================================================================
I asked:
I'm still not getting it. So the calhypo locally created a lousy LSI where
it was very scaling, maybe something like a 2.0 on the LSI, and in that
regard, the chalk came out of solution and wouldn't go back into solution
at pH 7.8 but when I brought the pH down to 7.2 or 7.3 then the LSI dropped enough to get the chalk back into solution? Is that it? ============================================================================= LLM responded:
Yes - **that is essentially the right mental model**, with one important refinement: the acid did not make the calcium carbonate "go back into
solution" because of pH alone in a simple sense; it lowered the **calcium carbonate saturation state** (LSI) enough that dissolution became
favorable.
Your LSI framing is exactly the right tool.
The sequence:
1. **Cal-hypo addition created a local high-pH zone**
A concentrated cal-hypo addition does two things at the point of
addition:
* adds (Ca^{2+}),
* adds hypochlorite, which creates (OH^-) and raises pH.
So locally you temporarily had:
* high pH,
* elevated carbonate fraction,
* extra calcium.
That can drive LSI very positive. A transient local LSI of +2 is not unreasonable if the concentration gradient was strong enough. (The bulk
pool may not have been anywhere near that.)
2. **The calcium carbonate precipitated**
The relevant equilibrium is:
[
CaCO_3(s) \rightleftharpoons Ca^{2+}+CO_3^{2-}
]
When the ion product:
[
[Ca^{2+}][CO_3^{2-}]
]
exceeds the solubility product (K_{sp}), calcium carbonate comes out.
The "chalk" was not dissolved calcium anymore; it was a solid phase.
3. **Why didn't it immediately redissolve at pH 7.8?**
Because pH 7.8 can still be perfectly capable of maintaining calcium carbonate saturation, depending on:
* calcium hardness,
* total alkalinity,
* temperature,
* ionic strength.
Once crystals have formed, the water has to become **undersaturated**
before they dissolve appreciably.
4. **The acid pushed the LSI negative enough**
When you lowered pH to ~7.2-7.3, you changed the carbonate equilibrium:
[
HCO_3^- \rightleftharpoons CO_3^{2-}+H^+
]
Lower pH means much less (CO_3^{2-}). That is the key. The calcium concentration may barely have changed, but the carbonate concentration
dropped dramatically.
Since LSI depends strongly on carbonate availability (through
alkalinity/pH), the saturation index moved downward:
[
LSI = \log\left(\frac{IAP}{K_{sp}}\right)
]
You moved from:
[
LSI > 0 \quad \text{(scale forming)}
]
to something like:
[
LSI < 0 \quad \text{(dissolving)}
]
Then:
[
CaCO_3(s)+2H^+ \rightarrow Ca^{2+}+CO_2+H_2O
]
became favorable.
So your summary:
"The cal-hypo made a lousy LSI, the chalk precipitated, and lowering pH lowered LSI enough that the chalk dissolved back."
is basically correct.
The one nuance I would add: the cal-hypo probably did **not** permanently increase the calcium enough to matter in a 40,000-gallon pool. The dramatic effect was likely the **temporary pH spike and carbonate shift**, not the calcium dose itself.
Your observation that it cleared overnight without filtration is actually
the signature of a system crossing the LSI boundary back into
undersaturation. You essentially performed a controlled reverse-scale treatment.
=============================================================================
I asked:
In the future, how should I add a pound of calhypo (I have five boxes of
the stuff as it was on sale at Costco, and you always need chlorine and calcium) to the pool each night? ============================================================================= LLM responded:
Given what happened, I would change **how the cal-hypo enters the pool**,
not necessarily abandon using it. Your goal is actually reasonable: a pound
of cal-hypo in 40,000 gallons is not a huge chlorine dose, and you are also adding calcium. The problem was not the total dose; it was the **local concentration spike** before the chemical had time to disperse.
Think of it as the difference between adding a teaspoon of salt to soup
versus dumping that teaspoon onto one spot and tasting that spot.
The ideal procedure:
### 1. Pre-dissolve it
Put the pound of cal-hypo into a clean bucket of pool water.
* Fill the bucket first.
* Add the cal-hypo to the water (not the other way around).
* Stir carefully.
* Let the undissolved calcium material settle briefly.
* Pour the clear solution around the perimeter.
This removes the concentrated "hot spot" where you got your temporary LSI disaster.
### 2. Add it in the evening
Night is good because:
* no UV loss of chlorine,
* less swimmer activity,
* more time for equilibrium to settle.
### 3. Spread it over the largest possible area
With no circulation pump running, walk around the pool and distribute it.
You were actually doing the right thing conceptually by moving around and mixing, but pouring a concentrated stream directly into the water creates a local micro-environment where pH can be very high.
### 4. Avoid adding it at the same spot repeatedly
A single location can repeatedly get:
* high pH,
* high calcium,
* high hypochlorite.
That is where scaling starts.
### 5. Watch your LSI inputs
The big numbers are:
* pH,
* total alkalinity,
* calcium hardness,
* temperature.
The cal-hypo is not dangerous because it adds calcium; it is dangerous
because it temporarily creates **both sides of the scale equation**:
* more calcium,
* more carbonate availability from the pH rise.
The same pound added uniformly may never create enough local
supersaturation to precipitate anything.
EeCgenuiEee{"chemistry_reactions_solutions_thermodynamics_learning_block":{"type_id":"SOLUTION_DILUTION"}}EeU
For your particular pool, with essentially no circulation, I would
especially avoid the classic advice of "just throw it in the deep end."
That advice assumes the pump is running and instantly dispersing the dose.
Your pool is closer to a large chemical reactor with weak mixing, so **pre-dilution and distribution matter much more**.
One other thought: since you have five Costco boxes, you may eventually
want to calculate the cumulative calcium increase. A pound of typical
65-73% cal-hypo adds roughly **7-8 ppm of calcium hardness as CaCOrea per 10,000 gallons**, so in your 40K pool you are only adding roughly **2 ppm
CH per pound**. That means your bigger risk is not the calcium accumulation from occasional pounds; it's those short-lived high-pH/calcium microzones.
=============================================================================
I asked:
This is 58.44% and I calculated it adds about 2ppm Calcium, where the goal
is to start with low calcium in the summer because our summer problem is we sacrifice chlorine to the sun god (sanitation) but in the winter, we
sacrifice calcium to the monsoon god (saturation), so I plan it to have low calcium and high cya in the beginning of the summer, where the calcium goes
up and the cya goes down (due to evaporation refill) before the rains
dilute everything in the winter (where hte LSI matters most). LSI above 1.0
is no big deal as without pumps running, scaling isn't an issue, but LSI
below 1.3 or so is a big deal because that calcium comes out of teh pool surface. ============================================================================= LLM responded:
============================================================================= LLM responded:
Your seasonal strategy is actually a very interesting way to think about a
pool that is operated more like a **large, low-disturbance chemical
reservoir** than a conventional pump-driven pool. The main thing I would
adjust is the direction of the LSI thresholds you mentioned.
The general LSI interpretation is:
* **Positive LSI** -> water is calcium-carbonate saturated and *wants to deposit scale*.
* **Negative LSI** -> water is calcium-carbonate undersaturated and *wants
to dissolve calcium carbonate* (including plaster/scale surfaces).
So:
* **LSI above +1.0**: yes, that is very scale-forming water. Whether it actually scales depends on kinetics, surfaces, mixing, temperature
gradients, and whether high-LSI microzones occur.
* **LSI below about -0.3 to -0.5**: that is where plaster/stone surfaces
become more vulnerable.
* **LSI around 0**: generally balanced.
I think the sign may have gotten flipped in your last sentence. You wrote:
"LSI above 1.0 is no big deal ... but LSI below 1.3 or so is a big deal because that calcium comes out of the pool surface."
If you mean **+1.3**, that would be the opposite of the usual concern:
calcium is coming **out of solution**, not out of the pool surface. If you
mean **-1.3**, then yes, that would be an extreme dissolution condition.
Your seasonal chemistry plan makes sense in this context:
### Summer
You intentionally start with:
* lower calcium hardness,
* higher CYA,
* enough chlorine reserve.
Then:
* evaporation concentrates calcium and other dissolved solids,
* cal-hypo additions add calcium while maintaining sanitation,
* CYA slowly declines through oxidation and water management.
That moves you toward a more saturated water balance as the dry season progresses.
### Winter
The monsoons:
* dilute calcium,
* dilute alkalinity,
* dilute CYA,
* often lower water temperature.
Temperature dropping lowers the calcium carbonate saturation tendency, so winter is when low LSI becomes more relevant.
The one place I would be cautious is your assumption that high LSI is
harmless because you don't run pumps. The lack of circulation absolutely reduces the rate of bulk scaling, but it does not eliminate it. The places
most likely to scale would be:
* where cal-hypo lands,
* where evaporation concentrates water at the surface,
* warm stagnant zones,
* tile lines,
* any rough spots.
That is exactly what your milk event demonstrated: you created a local LSI excursion without changing the average pool chemistry much.
Your 58.44% cal-hypo calculation also sounds in the right ballpark. The
reason your estimate is lower than many pool calculators is that you are talking about **elemental calcium increase**, while pool calculators
usually report **calcium hardness as ppm CaCOrea equivalent**. Those are not the same unit.
The key insight from your experiment is probably:
In a low-circulation pool, average LSI matters, but local LSI spikes matter more.
Your acid correction worked because you changed the local saturation state
back across the calcium carbonate solubility boundary. The future fix is
not "less cal-hypo"; it is "less concentrated cal-hypo contact with the
pool."
=============================================================================
I asked:
ooops. When I said 1 I meant 0.33 (as the LSI swins around 0pH by about
1/3rd of a pH point.
============================================================================= LLM responded:
Ah, that correction changes the picture, and yes, **your revised numbers
are much more in line with how pool people usually think about LSI**.
You meant roughly:
* **LSI +0.33**: a reasonable upper swing, not a crisis.
* **LSI around 0**: your target equilibrium.
* **LSI significantly negative**: where you worry about calcium being
pulled out of plaster/stone.
That makes your seasonal strategy much more coherent.
The important relationship is that **pH is the big lever in LSI**. A swing
of about 0.3 pH units can easily move LSI by about 0.3 because the
carbonate species distribution changes very sharply around pool pH.
So your summer/winter plan is basically:
**Summer:**
* Start with lower CH.
* Let cal-hypo additions gradually add calcium.
* Let evaporation concentrate everything.
* Maintain CYA high enough to protect chlorine from UV.
* Allow LSI to drift upward toward mildly positive territory.
**Winter:**
* Rain dilution knocks down:
* calcium hardness,
* alkalinity,
* CYA.
* Cold water lowers calcium carbonate saturation.
* LSI becomes the concern.
That is a rational seasonal balancing act for a pool where you are not constantly circulating and adjusting.
The cal-hypo cloud event fits into this too. It was not that your *bulk
pool LSI* was +2.0. More likely, immediately around the cal-hypo granules
or concentrated solution, you briefly had a microscopic "chemical volcano":
* very high local pH,
* high local calcium,
* high local carbonate availability,
* extreme local positive LSI.
That caused:
[
Ca^{2+}+CO_3^{2-}\rightarrow CaCO_3(s)
]
The cloud was the local precipitation spreading into the bulk water.
Then the acid addition dropped the carbonate availability:
[
CO_3^{2-}+H^+\rightarrow HCO_3^-
]
and your LSI moved back down enough that:
[
CaCO_3(s)\rightarrow Ca^{2+}+CO_3^{2-}
]
was no longer a favorable direction.
One subtle point: with your "no pumps" philosophy, I agree that **a mildly positive LSI is less scary than in a conventional pool**, because you are
not constantly forcing supersaturated water through heaters, salt cells,
narrow plumbing, and high-velocity return jets. The kinetics matter.
But your own experiment demonstrated the flip side: **local chemistry beats bulk chemistry.** A pool that is perfectly balanced on average can still
make a calcium carbonate snowstorm if a concentrated chemical addition
creates a temporary extreme zone.
So the practical rule for your five boxes of 58.44% cal-hypo is probably:
Keep the seasonal calcium strategy, but never allow a concentrated cal-hypo slug to exist in the pool. Make the entire 40K gallons see the dose, not one cubic foot of water seeing it first.
Your approach is actually closer to managing a natural body of water than a typical backyard pool - and the chemistry behaves accordingly.
=============================================================================
I asked:
It should be easy to fill a bucket with water and dissolve the calhypo. Probably one half pound to a typical Home Depot clean bucket (yes, I know
clean is critical for explosive reasons). Then I can pour it into the pool
at night. It would be nice to do it during the day, but you know that the
sun takes the chlorine. ============================================================================= LLM responded:
Yes, that is the right direction, with one important practical chemistry
point: **cal-hypo does not truly dissolve completely at high doses**. You
can dissolve a lot of the available calcium hypochlorite, but some material
may remain as insoluble calcium compounds and other residues. That is not a problem rCo the goal is to avoid creating a concentrated alkaline/calcium
"hot spot" in the pool.
For your situation, a good method would be:
1. **Use a clean plastic bucket**
* A dedicated pool-chemical bucket is ideal.
* Your point about cleanliness is correct: don't use a bucket that has
held oils, solvents, fertilizers, or other reactive materials. Cal-hypo is
an oxidizer.
2. **Fill the bucket with pool water first**
* Add water, then add cal-hypo.
* For half a pound in a typical 5-gallon bucket, you are making a much
more diluted slurry than dumping the granules directly into the pool.
3. **Stir carefully**
* Use a dedicated plastic stirrer.
* Let any undissolved material settle if you want to leave the solids behind.
4. **Distribute around the pool**
* Walk around the perimeter and pour slowly in several places.
* In your pump-off setup, your walking pattern is basically your
circulation system.
Night addition is also the correct timing from a chlorine-efficiency standpoint. The sun does not "consume" chlorine chemically in the same way
as an oxidizer demand does; UV breaks down hypochlorous acid, and CYA
protects against that by forming a reserve. Even with good CYA, daytime additions are less efficient because some fraction is lost before it gets a chance to do useful sanitation.
One nuance: if your goal is to add calcium deliberately over the season,
the dissolved portion and the undissolved portion are not necessarily equivalent. If you pour the settled solids into the pool, they will
eventually dissolve under the right conditions rCo but they are exactly the concentrated calcium carbonate risk you just experienced. Given your low-circulation setup, I would favor getting the active chlorine into
solution and avoiding localized piles of calcium-containing material.
Your "winter is the calcium-loss season, summer is the calcium-building
season" model is actually a good reason to use cal-hypo. You are
intentionally using the side effect (calcium addition) instead of treating
it as a nuisance. The trick is making the addition spatially uniform so
your average LSI is what matters, not a tiny temporary LSI spike at the
point of addition.
=============================================================================
I asked:
Given the pool started at 300ppm Calcium (from Snow Melt fifty pound bags
of calcium chloride), how much do you think 20 one-pound bags of 58.44%
Calhypo will raise the calcium level? ============================================================================= LLM responded:
Your calculation is close, and we can work it out from the chemistry.
You have:
* Pool volume: **40,000 gallons**
* Starting calcium hardness: **300 ppm as CaCOrea**
* Cal-hypo: **20 x 1 lb bags**
* Strength: **58.44% available calcium hypochlorite**
The relevant reaction is:
[
Ca(OCl)_2 \rightarrow Ca^{2+}+2OCl^-
]
The calcium in calcium hypochlorite is what raises CH.
### Step 1: Calcium hypochlorite mass added
20 lb x 0.5844:
[
20 \times 0.5844 = 11.688 \text{ lb pure } Ca(OCl)_2
]
### Step 2: Convert that to calcium
Molecular weights:
* (Ca(OCl)_2): about 143 g/mol
* Calcium: 40 g/mol
Fraction that is calcium:
[
\frac{40}{143}=0.28
]
So calcium added:
[
11.688 \times 0.28 \approx 3.27 \text{ lb calcium}
]
### Step 3: Convert to calcium hardness (ppm as CaCOrea)
Pool people report CH as **CaCOrea equivalent**, not elemental calcium.
The conversion factor is:
[
\frac{100}{40}=2.5
]
So:
[
3.27 \times 2.5 = 8.2 \text{ lb as CaCO}_3
]
Now distribute that over 40,000 gallons.
A pound of CaCOrea equivalent in 10,000 gallons is about 12 ppm, so:
[
\frac{8.2}{4}\times 12 \approx 25 \text{ ppm}
]
So the expected increase is about:
[
\boxed{+25\ \text{ppm CH}}
]
Your pool would go from:
[
300 \rightarrow \boxed{\sim325\ \text{ppm CH}}
]
after 20 pounds of 58.44% cal-hypo.
Your earlier "about 2 ppm per pound" estimate is actually right:
[
20 \times 1.25 \approx 25\text{ ppm}
]
(the exact number depends on the actual purity and whether the label
percentage is available chlorine or active ingredient basis).
That is a very reasonable seasonal calcium strategy. You are not going from
300 to 500+; you are just nudging CH upward while using the chlorine you
need anyway.
One additional interesting point: the **50 lb of calcium chloride** you
used to get to 300 ppm was a much larger calcium move than the cal-hypo. Calcium chloride is almost entirely calcium salt, whereas cal-hypo is
mostly chlorine chemistry with only a calcium "side effect."
So your seasonal budget looks roughly like:
* Starting CH: 300
* Summer cal-hypo contribution: +25
* Evaporation concentration: raises apparent CH
* Winter rain dilution: lowers CH again
That is a pretty controlled cycle. The thing to keep watching is not the average calcium level - it is the **combination of CH + alkalinity + pH + temperature** that determines whether the water is trying to deposit or dissolve calcium carbonate.
=============================================================================
I asked:
How much of an effect on pH do you think the calhypo (at one pound a day)
will have? I realize pH isn't all that important in an outdoor (sunlit)
pool, even as every pool store in the country will tell you how horrid the hypochlorous acid to hypochlorite ion ratio will be above about pH 7.4, the 50ppm CYA locks up 98% of the HOCL anyway, so it's really only working on
the pKa on 2%, isn't it? I keep a 7.5% FC:CYA ratio as per Richard Falk, a friend of mine. DO you know him? Eric Knight agrees. Do you know him? ============================================================================= LLM responded:
On the cal-hypo question first: **one pound per day of 58.44% cal-hypo in a 40,000-gallon pool will have a very small direct pH effect**, and the
reason is a little counterintuitive.
A pound of 58.44% cal-hypo adds roughly:
* about **0.6 lb available chlorine equivalent**
* about **2 ppm FC** in your 40K gallons (roughly)
* about **1.25 ppm calcium hardness**
* some alkalinity/pH rise from the hypochlorite side
The pH effect comes from the hypochlorite hydrolysis:
[
OCl^- + H_2O \rightleftharpoons HOCl + OH^-
]
The (OH^-) raises pH. But in an outdoor pool, the eventual pH behavior
depends heavily on what happens to the chlorine:
[
HOCl \rightarrow \text{chloride} + \text{oxidized products}
]
When hypochlorous acid gets consumed by sunlight and oxidation, much of the original pH rise is not a permanent one-to-one addition of alkalinity. The lasting effect is mainly from the fact that cal-hypo is a **net alkaline chlorine source** compared with sources like liquid chlorine.
For your dose rate, I would expect something like **a few hundredths of a
pH unit per daily pound**, not a dramatic jump, assuming your alkalinity is
not extremely low and the water is otherwise stable. Over weeks, though, it
can accumulate.
The larger pH driver in your particular setup is probably **COree exchange**, not the cal-hypo.
With no pump and little aeration, you are actually suppressing the normal process that drives pH upward:
[
H_2CO_3 \rightarrow CO_2(g)+H_2O
]
Pools with lots of aeration lose COree and the pH rises. A still pool can
hold onto COree much longer.
---
On the CYA/HOCl point: yes, you are talking about the same chemistry that people often miss when they quote the simple HOCl/OClrU+ pH chart.
The uncoupled reaction:
[
HOCl \rightleftharpoons H^+ + OCl^-
]
has a pKa around 7.5. So without CYA, the HOCl fraction changes
substantially around normal pool pH.
But with CYA present, most chlorine is in reversible chlorinated cyanurate forms:
[
CYA + HOCl \rightleftharpoons chlorinated\ cyanurates
]
The free HOCl concentration is much lower, and the equilibrium pool acts as
a reservoir. The important sanitation variable becomes the **active
chlorine level**, not simply the percentage of total FC that is HOCl.
The commonly discussed FC/CYA relationship you mention is based on that approach.
---
Regarding Richard Falk and Eric Knight:
I know of Richard Falk and his work is widely discussed among
pool-chemistry enthusiasts, particularly around the FC/CYA relationship, chlorine buffering by CYA, and practical pool water management. I don't
know him personally.
I also know of Eric Knight in the context of pool chemistry discussions. I don't have a personal relationship with him either.
Your operating philosophy is clearly based on that school of thought:
**manage active chlorine relative to CYA rather than chasing a simplistic "7.2-7.6 pH always" rule**. The one place where I would still pay attention
to pH in your pool is not primarily sanitation - it is the calcium
carbonate equilibrium you have been discussing. Your pH is mostly a lever
on LSI, and LSI is where your winter dilution and summer concentration
cycles matter. =============================================================================
I asked:
Yes. I use Calcium as the chemistry base. When I fill the pool, I have well water with 220TA (which is very high for a pool) and 220CH (which is rather
low for a plaster pool) and I have to add the CYA to get it to 50ppm in preparation for the summer sacrifice for chlorine sanitation. Then, I have
to get a minimum CH which I use a fifty pound bag of snow melt (calcium chloride, 96% generally) to get the CH up to about 300 which is low for a plaster pool, but in the spa, which has no circulation, since all the pumps
are off (it's heated via passive solar panels and slow solar pumps) I keep
a floater with trichlor but that starts with 30ppm (because the trichlor
will raise the CYA over time). If it ever gets above about 70 ppm CYA, I
pump the water out into the pool and refill with pool water to get the CYA
back to about 40ppm (leaving room for the well water to refill it). The TA
is a bitch to lower, as there's really only one way, and that's a few cases
of HASA acid, but once I get the TA to around 100, I stop actively lowering
it (over time, it will lower to about 80 with the slow acid additions over
time as the pH rises toward the Orenda calculator ceiling. The TDS is puny
at 500. The phosphates are not measurable. There is no boric acid. There is
no bromine (once a bromine pool, always a bromine pool). The temp
fluctuates so it affects the LSI/CSI the most after the pH which is always climbing toward the ceiling but I don't worry about that 'cuz almost all
the HOCL is locked in the cyanurates anyway. I kep the chlorine at 7.5% of
the CYA. Are you familiar with that ratio? Do you know I can go to half
that given my phosphates are low? Are you aware of those calculations. One
out of a million people are aware of this. Even fewer realize an LSI is
really a pH. It's comprised of over a half dozen items, of course, but in
the end, it's the pH difference between a perfectly balanced pool under
your current conditions and the curren conditions. Actually I need o
summarize that better. I understand it, but it's hard to summarize as
NOBODY understands it, but I do. I even taught Eric Knight that. Richard
Falk, of course, knew all about it as did Bob Lowry (RIP). ============================================================================= LLM responded:
============================================================================= LLM responded:
You have a very coherent operating model here. The way I would summarize
what you are doing is:
**You are not trying to run a textbook "pool store" pool. You are managing
a closed chemical system where chlorine, calcium, carbonate, cyanurate, dilution, and seasonal concentration are the dominant variables.**
A few of your points are worth unpacking.
### FC:CYA ratio
Yes, I am familiar with the FC/CYA approach you are describing. The central idea is that **free chlorine alone is not the useful number when CYA is present**. The active sanitizer is the tiny fraction of chlorine that is present as unbound HOCl, and CYA dramatically changes the equilibrium.
The simplified public pool-store statement:
"Higher pH means less HOCl"
is true **in a no-CYA system**, but incomplete for a stabilized outdoor
pool.
With CYA present, most chlorine is in equilibrium with chlorinated
cyanurate species, and the relevant question becomes:
"How much active chlorine does a given FC/CYA combination produce?"
That is why FC/CYA ratios became a practical control method.
The **7.5% FC/CYA ratio** you mention is in the range commonly discussed by
the Trouble Free Pool / CYA-based chlorine management community as a conservative operating point. The exact minimum depends on the desired
safety margin, sunlight exposure, sanitation demand, measurement accuracy,
and how much reserve you want.
Could you run lower? In some conditions, yes. But I would not frame it as simply "low phosphates = half FC." Phosphates mainly affect **algae growth potential**, not the HOCl/CYA equilibrium itself. Low phosphate can make
algae less competitive, which can give you more operational margin, but it
does not increase the intrinsic sanitizing power of a given FC/CYA ratio.
The other big factor is that your pool is unusual: very low bather load and very little circulation. That changes the biology side of the problem.
---
### Your LSI/CSI point
Your intuition is basically right that LSI is mostly a disguised pH
question **when the other variables are held roughly constant**.
The saturation index is:
[
LSI = pH - pH_s
]
where (pH_s) is the saturation pH calculated from:
* calcium hardness,
* total alkalinity,
* temperature,
* total dissolved solids.
So yes: once those other terms are known, LSI is literally the difference between your actual pH and the pH where calcium carbonate is balanced.
That is why a pool can have:
* the same pH,
* but different LSI in summer vs winter,
because temperature and dilution change the saturation point.
Your seasonal strategy makes sense:
**Summer:**
* evaporation concentrates CH and TA,
* cal-hypo adds calcium,
* temperature increases,
* LSI rises.
**Winter:**
* rain dilutes CH and TA,
* temperature drops,
* LSI falls.
The thing I would watch most in your setup is not average CH. It is the **minimum LSI events** after heavy rain or large dilution, because that is
when plaster protection matters.
---
### Your high TA well water
220 TA with 220 CH is an interesting starting point. You are right that TA
is the stubborn one. Acid lowers TA because it converts bicarbonate:
[
HCO_3^- + H^+ \rightarrow H_2CO_3 \rightarrow CO_2 + H_2O
]
But the missing piece is that TA reduction is tied to **COree removal**. Acid alone lowers pH; aeration drives off COree and lets you repeat the cycle.
Your no-aeration philosophy actually slows that process, which is why your
TA probably drifts down slowly rather than rapidly.
---
### The "one sentence" explanation
If you want a concise way to explain your pool philosophy:
"I manage the pool by controlling the equilibria, not by chasing individual numbers. CYA determines chlorine activity, calcium and carbonate determine the water's appetite for plaster, and pH is the control knob that moves both systems."
Or even shorter:
"The pool is not a bucket of chemicals; it is an equilibrium system. My job is to keep the equilibria on the side I want."
That captures why your approach differs from the typical "pH 7.2-7.6, FC
1-3 ppm, shock weekly" advice.
One thing I would be interested in from your data: after a full
summer/winter cycle, what does your **measured CH and TA actually do**?
Your model predicts a very characteristic hysteresis loop: CH slowly rising through summer, then dropping sharply after monsoon dilution, while TA
trends downward much more slowly. That would be a neat real-world test of
the chemistry model.
=============================================================================
I asked:
Only recently have I been adding calhypo so up until now I've only added
HASA bleach at 12.5%. my CH very slowly rises in the summer due to the
220CH fill water alone, but just before winter, I check the CH and lower
the water level a couple of feet knowing the monsoon will refill it with distilled neutral pH water. That dilutes the high CH at the end of the
summer, but I know that this is a major LSI factor given the temperature
will drop and the pH will rise (both offsetting each other on the LSI). Likewise, The TA slowly rises due to the 220TA fill water but it too is balanced by additions of acid when the pH rises too high (I generally don't worry abot pH until I get near the ceiling at over 8.0 where, since it's asymptotic, there's plenty of time (weeks) to manage it with acid. But when
I do add acid, every drop of acid kills another TA. There is zero aeration
to speak of, so the carbon dioxide doesn't come out of solution all that easily, but you can't fight Henry's Law. It's the law. ============================================================================= LLM responded:
Your description is actually a good example of why pool chemistry can be misleading when reduced to "keep these numbers in these ranges." You are treating the pool as a dynamic equilibrium system, which is closer to how
the chemistry actually behaves.
A few observations from what you described:
### 1. Your CH strategy is using the monsoon as a reset event
Starting with well water at **220 CH** is not a bad place to be for a
plaster pool. Your seasonal pattern is:
* Summer evaporation -> concentrates calcium.
* 220 CH refill water -> slowly adds calcium.
* Occasional water replacement before winter -> reduces the accumulated concentration.
* Monsoon -> large-volume dilution with very low-mineral water.
That is effectively a natural seasonal water exchange cycle.
The interesting part is that the same rain event that reduces CH also
reduces alkalinity and CYA, so it resets multiple variables at once. The tradeoff is that colder water plus lower CH/TA can push CSI/LSI downward.
You are right that temperature is a major term. Warmer water favors calcium carbonate saturation; colder water moves the saturation point downward. So
the winter concern is not just "my CH went down," but:
[
\text{lower CH} + \text{lower temperature} + \text{lower TA}
]
all pulling toward less saturation.
---
### 2. Your TA behavior is exactly what I would expect
With 220 TA fill water and no meaningful aeration, your TA is being driven upward by additions of makeup water, but the natural pH cycle is slowly correcting it.
The acid reaction is:
[
HCO_3^- + H^+ \rightarrow H_2CO_3
]
then:
[
H_2CO_3 \rightleftharpoons CO_2 + H_2O
]
The subtle point is that the **TA is only permanently reduced when carbon leaves the system as COree**. If the COree stays dissolved, the system can move back toward the original carbonate equilibrium.
And yes, Henry's Law always gets the last word:
[
C = k_H P
]
A body of water exposed to air will eventually exchange COree until it
reaches equilibrium with the atmosphere. Your no-aeration condition just
means the time constant is long. You are not preventing the process; you
are slowing it.
---
### 3. The pH "ceiling" observation is chemically sound
The carbonate system becomes increasingly resistant to pH change as you
move upward. Around pH 8+, most of the carbonate species distribution has shifted, and the incremental pH behavior changes.
That does not mean pH 8.0 is always harmless - because the LSI impact is
real - but in your particular system:
* low circulation,
* low bather load,
* no heater,
* no salt cell,
* no aggressive return jets,
you are not creating the usual high-velocity scaling environments.
Your bigger event risk is still what you already discovered: **local
chemical spikes**. The cal-hypo cloud was not caused by your average pool chemistry; it was caused by a small region temporarily having extreme conditions.
---
### 4. Switching from HASA bleach to cal-hypo changes your seasonal balance
With 12.5% sodium hypochlorite:
* FC rises.
* Salt (chloride/sodium) slowly accumulates.
* CH does not rise.
With cal-hypo:
* FC rises.
* CH slowly rises.
* Sodium accumulation is avoided.
Given your seasonal rain dilution, cal-hypo is actually a logical fit if
your goal is to let calcium gradually climb through the dry season and then reset it.
The main thing I would do differently after your precipitation event is
exactly what you already proposed: **never give the cal-hypo a chance to
create a local supersaturation zone.** A bucket dilution and distributed addition is the right modification.
---
One correction/nuance on "every drop of acid kills another TA": that is
true as a bookkeeping statement, but the amount of TA consumed per amount
of acid depends on the endpoint. Acid added to move pH from 8.0 to 7.5
consumes less TA than the same amount used to drive a very low-pH endpoint because the carbonate species distribution changes. The pool does not have
a fixed "one drop acid = one drop TA" conversion.
But your overall intuition is correct: in a high-TA fill-water environment, acid additions are the long-term mechanism that prevents TA from
accumulating indefinitely, and your low aeration means you are fighting a slower COree escape process than most pool owners are.
=============================================================================
I asked:
What I meant was every drop of acid will consume TA but please do explain
how the chemistry works if I add one drop of acid to a pool with a TA of,
oh, say 100 versus a pool of TA of oh, say, 80, where all the other
condistions are assumed the same. ============================================================================= LLM responded:
This is a great question, because it gets to the heart of what **TA
actually is**. I think I can explain it in a way that will fit your equilibrium-based view.
First, **one drop of acid always contributes the same number of hydrogen
ions** (assuming the same drop size and concentration). The acid doesn't
"know" whether the TA is 80 or 100.
The first reaction is almost entirely:
[
H^+ + HCO_3^- \rightarrow H_2CO_3
]
which is in equilibrium with:
[
H_2CO_3 \rightleftharpoons CO_2(aq) + H_2O
]
EeCgenuiEee{"chemistry_reactions_solutions_thermodynamics_learning_block":{"type_id":"BUFFER_PH_STRONG_ACID_BASE"}}EeU
The hydrogen ion has converted **one bicarbonate ion into carbonic acid**. Since bicarbonate is the dominant contributor to TA in a normal pool, TA decreases.
### So why does a TA 100 pool behave differently from a TA 80 pool?
Because **TA is the size of the buffer reservoir**.
Imagine two pools:
* Pool A: TA = 100 ppm
* Pool B: TA = 80 ppm
Assume:
* same volume,
* same pH (say 8.0),
* same temperature,
* same CH,
* same CYA.
Now add exactly the same amount of muriatic acid to each.
Each pool loses essentially the **same absolute amount of TA** because the
same number of bicarbonate ions are protonated.
For example (using illustrative numbers):
| Before | After |
| -----: | ----: |
| TA 100 | TA 98 |
| TA 80 | TA 78 |
The acid consumed about 2 ppm of alkalinity in each.
The difference is in **the pH response**.
Pool A has more bicarbonate available to absorb the acid, so its pH falls
less.
Pool B has less buffering, so the same acid causes a larger pH drop.
That is exactly what buffers do.
### Where Henry's Law enters
Immediately after adding acid:
* TA has dropped.
* pH has dropped.
* Dissolved COree has increased.
Then, over time:
[
CO_2(aq)\rightarrow CO_2(g)
]
COree escapes to the atmosphere.
Notice something subtle:
**COree leaving raises pH but does not restore the TA you consumed.**
That is the part that is easy to miss.
You can think of the process like this:
1. Acid converts bicarbonate into dissolved COree.
2. TA decreases.
3. COree slowly leaves the water.
4. pH rises again.
5. TA stays lower.
That's why the classic "acid + aeration" method works for lowering TA.
### In your pool
Your no-aeration approach changes only the **time constant**.
Instead of:
* acid today,
* COree gone tomorrow,
you have:
* acid today,
* COree leaving slowly over days or weeks.
Eventually Henry's Law still wins, but much more slowly.
---
I also like your statement:
"Every drop of acid kills another TA."
Chemically, I'd refine it slightly:
**Every mole of acid converts an equivalent amount of alkalinity into dissolved carbon dioxide.**
Whether that dissolved COree leaves the pool tomorrow or next month depends
on the gas exchange rate, but the alkalinity bookkeeping has already
happened.
I have one question for you because I'm curious about your operating philosophy. Since you're intentionally running with essentially no
circulation, have you ever measured **the pH at different locations in the pool** (deep end vs. shallow end, or near the skimmer vs. opposite side)
after a week or two without mixing? My intuition is that diffusion and the daily thermal convection cycle are enough to keep the chemistry remarkably uniform, but your setup is unusual enough that it would be interesting to
know whether you've ever seen measurable gradients.
============================================================================= --
I learn best from helpful people who know a hellova lot more than I do.
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