High PH and High TA

by Frost

High PH and High TA

by Arctic Frost

I see many questions about high pH and low TA but what about high pH and high TA? I've added pH minus to our pool in the suggested amount to lower TA. I haven't seen any results yet but I only added the Minus pH about 5 hours ago.

This is my first pool as we've just bought a house in Arizona. The last owners left the place in exquisite condition and the pool goes without saying. The pump always reads 10 PSI so I haven't backwashed yet. I brush every other day and am just now adding chemicals.

Everyone has a different opinion as to what's best, from "just brush and add chlorine" to "test everyday and add those chemicals". The pool is always clear and pretty, not much scaling but some.

I believe it's getting a slightly green tinge but so slight I'm not even sure. I got those water bugs so I'm laying odds algae is growing.

That's why I opted to start to mess with the chemicals.

Arctic Frost

PS - We're from Alaska so this pool stuff is all new to us

Thanks for your question. The very first thing I would recommend is getting a Taylor Reagent FAS-DPD K-2006 pool water test kit. It's the best and will give you the most accurate pool chemical readings.

I'll start with the first paragraph of your question and move down. When adding any chemicals you need to wait for one full turn-over of the pool water to re-test. This means that all of the water has gone through the filter and back into the pool through the returns. This normally is about 8 - 10 hours.

Example: The GPM (gallons per minute) for a pool pump is 40 and we have a 20,000 gallon pool. 40 X 60 minutes = 2,400 gallons per hour
20,000 gallon pool divided by 2,400 GPM = 8.3 hours. So it would take 8 hours for one turn-over and then re-test the water.

With the FAS-DPD test kit you'll be testing for chlorine, combined chlorine, pH, TA, calcium hardness, and cyacuric acid
(CYA). Chlorine is the sanitizer for the pool and you'll want to keep that between 2 - 4 ppm. pH is 7.6 - 7.8, TA is 80 - 120 ppm, Calcium Hardness is 150 - 250 ppm. I know in many parts of Arizona the hardness level of the water can be 300 or more, so you might have an issue with scaling. That's why it's important to keep the TA in check. CYA is 30 - 50ppm.

This is the stabilizer for the chlorine and can be found in Tri-chlor pool chlorine tablets.
You'll be o.k. in testing a couple of times per week and any chemical additions or adjustments should be done in the evening. This way the pool has the best chance against the hot sun.
If you have a light green tinge to the water, it's safe to say you might be getting pool algae. I would suggest you shock the pool. There's a chart on the chlorine link above to tell you how much pool chlorine to add.

Don't worry too much about a slightly high pH. The main thing is to get the TA down. You'll want to add the acid with the pool pump off. Very gently sweep the bottom to break up and hot spots. Allow it to sit for 2 - 3 hours, turn the pump motor back on and allow for one full turn-over, then re-test. When making any pool chemical adjustments the main thing is to be patient. It might take a few applications before you get the water balanced.

The most important aspect is to stay on top of it and be proactive be testing twice per week. If the pH does come down by adding the acid, don't worry. Through filtering, swimming and splashing around, the pool will be burning off the CO2 (carbon dioxide) and the pH should come up on it's own.

You can use simple muriatic acid to lower both the TA and pool pH levels. Get a tab floater and keep it full of chlorine tabs, but also keep an eye on the CYA. Hope this helps and good luck with your pool.

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