Bromine Chemistry Question

[CarlD]

Okay, I am comfy waiting for this long process to finish.... I am just concerned about how to know when I reach 110-120 TA if my tests are off. pH has already risen from 7.0 to 7.2 in 3 hours. (I added a slight splash from the slide too). Looks like more MA tonight! I will keep an eye on the FC with the pool open and CYA<30, and add more dichlor tonight if FC drops to around 2.
And by the way, Carl, I have never in 8+ years had to raise my pH; I always have to lower it. That may have been my old bromine pool-store treated water, but also may have something to do with my fill well-water.

Generally, if you find your pH is always rising and you have to lower it, you sho0uld lower TA to anywhere from 60 to 80. If you find it's always falling, you'd want to raise your T/A till it stabilizes.

[PoolDoc]

As Carl suggested, the numbers are less important than they sometimes seem. On a vinyl pool, if your water is clear, and your pH is not too low, and you aren't adding copper . . . you're not going to damage your pool.

The Taylor TA test is probably the most accurate one you have access to -- so if you are using it correctly, those are the results you should trust. But there is room for 'operator error' any time you do a titration, whether it's with a glass buret and an Erlenmyer flask, or with a 100 mL plastic tube and 3 dropper bottles. If you want to be SURE you're doing it right, check out these videos:
https://www.youtube.com/playlist?lis...99CY_BQXE1Jx6s
https://www.youtube.com/playlist?lis...-ZRW_OFLP4jNO4

But honestly, if you'll just relax a bit, things will be easier, and you'll get better at the details.

One absolutely key point: no pool EVER runs exactly by the book. The real world is always more complicated than the 'rules', and if you try to make the two sync up perfectly, you'll go nuts. Twenty-five years ago, we were told that the IgE levels found on my then 3 year old son were impossible: if he REALLY had those levels, he'd be confined to an allergy bubble in Arizona. But, those levels were confirmed with subsequent testing, and yet he's never been confined, though I did give him allergy shots for 7 years. Twenty years ago, my pastor was told that his cholesterol levels were close to the highest ever reported, and that he should plan for a short life expectancy. He's still alive, though he did have to have a bypass 3 years ago.

Bottom line: no set of tests, even with multi-million dollar equipment, will fully describe what happens in YOUR pool. But, with practice, you can get 'close enough' with the Taylor K2006. And that's really all you need.

[FormerBromineUser]

Okay, I'm relaxing or at least trying my best... Here are my morning numbers:
pH 7.5
FC 2.6
CC 0.3
TA 200 but if I go as pink/red as the video shows, it's more like 220.
I took today's sample into Leslie's, and they agree with pH but say that my TA is now 120. To recap, their results were 170 initially, 150 after first MA dose, and 120 after second MA dose. Is that a fairly typical change between treatments? If so, I am going to trust their numbers for now. After adding almost 2G total MA and aeration, my TA cannot still be at 200. (I wouldn't think so anyway). After work, I am going to Leslie's and have them test TA with MY reagents and see what they get. I also think I will do one more round of acid/aeration to aim for a Leslie's TA of 100. In-The-Swim also tests with Taylor reagents and I may run there with a water sample for a third result.

[PoolDoc]

If you carry water to a store to be tested for TA, be SURE that you (1) fill the bottle 100%, and leave NO air space, and (2) keep it cool. Otherwise, you'll get a bogus result.

Chlorine, pH, and TA results are 'perishable' and will not be reliable if (a) the sample is improperly collected (air space, mainly), (b) mishandled (shaken, vibrated, etc.), (c) overheated, or (d) stored too long -- 6 hours max, mainly for chlorine.

Actually, if there's oxidizable goo in your pool -- likely during startup -- you'd almost have to 'race' the sample to the store to get a result as accurate as your home test. And if you half fill a bottle and then agitate it (rolling around on the floor, driving a rough road, etc.) the sample will be read higher in pH and lower in TA than is actually the case in your pool.

[FormerBromineUser]

Hmmm, interesting. I am going to agitate a sample at home to see if I get a lower TA reading.
Do you agree that my TA must have come down somewhat after two series of MA and aeration? You said it would be a long process but if I still really am at 200, nothing has changed.

[FormerBromineUser]

Results:
Home: No difference in TA after agitation. TA still 220-230 depending on how dark a pink-red I go for.
In-The-Swim: TA 240 and he went dark like my 230
Leslie's: First he used his reagents. TA 110, then mine TA 150. He stops when color is greyish.
So, I will trust my reagents and just be frustrated that there has been no change in TA after 2 full cycles of MA.

I think I may have figured out my problem, however. Even though I read the directions over and over.... I goofed and am feeling pretty embarrassed.
Your instructions say:
4.) Begin aerating.
5.) Test your pH AND your alkalinity. Continue adding acid to MAINTAIN your low pH until your alkalinity reaches your target value. Once it does, continue aerating, but allow the pH to rise to the normal level.
I have been getting my pH down to 7.0 and then aerating to bring it back up to 7.5/7.6 and then lowering it back to 7.0 and aerating back up to 7.5/7.6. I see that your instructions say MAINTAIN low pH. I am now going to keep it around 7.0. I will reduce the amount of aeration at least until I know the MA has completely circulated.
Does that make sense? In the meantime, should I continue with 1C dichlor every night or switch to the calcium hypochlorite?

[PoolDoc]

I'm going to have to give you some different instructions.

1. Test your pool's pH each evening. If it's above 7.2, add 1/2 gallon of MA. Make sure the pump runs for at least 4 hours after. Do NOT test TA or CH during these 3 days!!! Continue to aerate, using whatever approach you've chosen.

2. After 3 evenings of testing pH and adding MA **as needed**, the following (fourth!) day test the TA.
==> If the TA is <150, do not add acid for 3 days. Do *NOT* test the TA again for 3 days. Discontinue acid additions during this period.
==> If the TA is > 150, recycle to #1 above.

3. After waiting 3 days (after a TA reading < 150 ppm), retest both pH and TA, and report results here. Do NOT test either pH or TA during the 3 days you wait.

OK?

Under NO conditions should you ("BromineUser") test TA more than 2x per week.