TA Confusion

[CoolCajun]

I am confused. The instructions that came with my TF-100 test kit states that "TA for manually chlorinated pools is 100-120 ppm." The Pool School app states that the ideal TA is between 60-80, and recommended is 50-90. So, what is it?

Currently, my TA is 120 & my ph keeps drifting down, from 7.6 (after adding borax) to the current level at 7.2. And from the last few weeks I have been battling this same scenario where it will keep drifting down until I add borax (about every 2 weeks or so).
It is extremely hot & humid here and water evaporation is a real thing, so I do have to add water every few days. But it is my understanding that the only thing that lowers ph or TA is acid, not dilution. Right?
I don't have any type of fountain for aeration but yesterday I managed to get a jet return to turn to break the water. But that takes time to raise ph (days, weeks, months?).
Thanks for any help.

 

[Msch99]

PH drifts down? Not sure I have seen that issue in forum unless something added to lower it. What all chemicals have you added?

TA is fine down to 50 or until you find the TA where the PH only rises slowly. (Apparently not your issue.)

Check TA and PH of your fill water to see what influence filling has.

 

[CoolCajun]

I will check the TA & PH of the fill water (community water is the source).
As far as chemicals, just liquid chlorine to supplement the automatic chlorinator and the borax.
You mention how low TA is acceptable, but how high is acceptable? 120, 90, or 80?
Thanks. I will reply back with my results.

 

[proavia]

You may want to quit using the automatic chlorinator - I assume it uses tabs/pucks. The tablets are acidic. Go with liquid only and let us know if the issue improves.

Post fill water FC, CC, pH, TA and CH

Post a full set of current test results from your TF-100
FC
CC
pH
TA
CH
CYA
Water temp

Just so we all have a baseline to go off of. Be sure to hold all reagent bottles completely vertical and dispense the drops in about one second intervals.

 

[Richard320]

The instructions with the test kit are old. The website recommendations have evolved some. Hence the discrepancy. Go by the website and/or poolmath.

If you're chlorinating with pucks, you're constantly adding acid which will drive down pH and TA, as you've seen. You're watching it, so you probably haven't damaged anything. Check out these pictures.

Also if you're chlorinating with pucks, you're constantly raising the CYA level, which means you'll need to raise the FC level to keep algae at bay. FC/CYA Levels

 

[CoolCajun]

Actually, I had turned the chlorinator way down about 2 weeks ago when I read that the tablets could be causing the problem. I add 1 gallon of 10% chlorine about every other day. The chlorinator is set on 1.5 on a dial that goes up to 5. Takes about 10-12 days to deplete.
FC 4
CC 1
PH 7.2 (color is weak)
TA 120
CH 120
CYA 70 (a little high, but expecting a lot of rain this weekend)
water temp 88 degrees

 

[proavia]

Your FC of 4 is below minimum for your CYA. At CYA 70, your minimum is 5 and target is 8-10. See FC/CYA Levels - your CC of 1 is a little concerning, given your low FC. Suggest you do an Overnight Chlorine Loss Test tonight to help rule out any algae issue.

Find a way to aerate your pool water to help get the pH up to 7.5-7.8

Empty tabs out of the chlorinator - completely.

 

[CoolCajun]

Your FC of 4 is below minimum for your CYA. At CYA 70, your minimum is 5 and target is 8-10. See FC/CYA Levels - your CC of 1 is a little concerning, given your low FC. Suggest you do an Overnight Chlorine Loss Test tonight to help rule out any algae issue.

Find a way to aerate your pool water to help get the pH up to 7.5-7.8

Empty tabs out of the chlorinator - completely.

To perform the OCLT, do I also turn off the pump (circulates water). The instructions do not mention this.
Not sure how to aerate. It is just a plain rectangular pool. I did get a return jet turn up to break the water, but how long does it take to raise ph in this manner (just curious, I am not going anywhere).
Thanks.

 

[proavia]

Leave pump running for Overnight Chlorine Loss Test to keep the water fully mixed. Be sure to bring FC up close to upper target number tonight. And the chlorinator has to be empty too. Test FC about 30 minutes after last add tonight after dark. Then test again in the morning before the sun hits the pool. The difference between the night FC and morning FC tests is your overnight FC loss.

Having a return pointed up to break the water surface helps with aeration. You can also fashion an aerator type fountain to spray water into the air - which will help raise the pH faster.

 

[CoolCajun]

The instructions with the test kit are old. The website recommendations have evolved some. Hence the discrepancy. Go by the website and/or poolmath.

If you're chlorinating with pucks, you're constantly adding acid which will drive down pH and TA, as you've seen. You're watching it, so you probably haven't damaged anything. Check out these pictures.

Also if you're chlorinating with pucks, you're constantly raising the CYA level, which means you'll need to raise the FC level to keep algae at bay. FC/CYA Levels

Thank you for the update! I looked at the pictures, but I don't have a heater so hope there hasn't been any damage to other parts. The TA has dropped to 110 just be emptying out the chlorinator. The PH is holding steady at 7.2 and not drifting down anymore in the last 3 days, so I will take that as a positive change. We have had some rain, so I hope that will add aeration. I still can't wrap my head around that dilution doesn't drop TA. I may have to resort to adding a small amount of muriatic acid to lower TA some more. A little of that goes a long way. Thank you again for the update!

 

[CoolCajun]

Your FC of 4 is below minimum for your CYA. At CYA 70, your minimum is 5 and target is 8-10. See FC/CYA Levels - your CC of 1 is a little concerning, given your low FC. Suggest you do an Overnight Chlorine Loss Test tonight to help rule out any algae issue.

Find a way to aerate your pool water to help get the pH up to 7.5-7.8

Empty tabs out of the chlorinator - completely.

Ok, I thought CC of 1 was good. So, I emptied the chlorinator & turned it off. Added liquid chlorine to bring up FC to 10ppm. Then I got to work brushing. Thunderstorms prevented me from preforming the OCLT Friday, so that gave me more time to brush & hold the FC at 10. Sunday morning results showed the FC dropped by .5 and the CC was .5. So those 2 days paid off. We also have had Saharian dust this past week (always something!).

The TA has dropped to 110 from 120 and the PH is holding steady at 7.2 (no more drifting down). Last resort, I may try very small doses of muriatic acid to get the TA is range. Rain is forecasted for all this week so that will help with aeration.

I am a little nervous about sanitizing with just liquid chlorine. We have a lot of sun. Do I test twice a day until I get the hang of it?

Thanks again for your help.

 

[scottts]

Your CYA of 70 will protect the liquid chlorine you use.

 

[Richard320]

You're not just sanitizing with liquid chlorine. It wouldn't last. You already have CYA in the water from the pucks, and it's shielding the chlorine. What you're doing is replenishing the part of those tablets that disappears and reusing the part that stays.

And don't be messing with the TA! Your pH is already at the low end of acceptable. Don't add any acid to "fix" TA or you'll make your pool unswimmable. What are you after? A clear sanitary pool to swim in, or some "ideal" numbers you don't really understand yet? So what if TA is high? It doesn't cause algae. It doesn't cloud the water. It's not toxic. It's mostly baking soda, and people brush their teeth with that! High TA will cause pH to rise a little faster, and you actually need that.

 

[BR1]

And don't be messing with the TA! Your pH is already at the low end of acceptable. Don't add any acid to "fix" TA or you'll make your pool unswimmable. What are you after? A clear sanitary pool to swim in, or some "ideal" numbers you don't really understand yet? So what if TA is high? It doesn't cause algae. It doesn't cloud the water. It's not toxic. It's mostly baking soda, and people brush their teeth with that! High TA will cause pH to rise a little faster, and you actually need that.

Glad I read this response. My TA is based on the TF kit. I have no reason to mess with it at this point if everythign else is good?

 

[Richard320]

Glad I read this response. My TA is based on the TF kit. I have no reason to mess with it at this point if everythign else is good?

Yep. Only two reasons to attack TA: imminent danger of calcium scale or you're tired of daily acid additions to keep pH in line. And it's funny -- the cure for daily acid additions is to add acid every day, or even twice a day, until you've beaten TA down. Same amount of acid overall, just in a shorter time span.