# Thread: I am a little confused with the calculator

1. ## I am a little confused with the calculator

I am a little confused with the calculator. The numbers just don't look right. My well water has a TA of 300 right from the tap. The calculator is telling me to add 31oz of acid. 31oz is not going to drop my TA to 120. The pool store is telling me I need to add 2 gallons to get it to drop.

2. ## Re: The Pool Calculator

What's the pH of the sample?
There's more to the equation than just TA.
You want to drop the TA, but you don't want to bottom out the pH while doing it.

3. ## Re: I am a little confused with the calculator

I am not sure what you were looking at, but the calculator doesn't have anything for calculating the amount of acid needed to lower the TA. You can't simply add acid to lower TA. If you did that you would lower the PH so much that it would damage the pool. Instead you need to follow the lowering TA procedure.

4. ## Re: The Pool Calculator

The Ph was just right at 7.5. So to drop the TA it is going to drop the Ph. The problem the high TA is giving me is that it's causing scaling on my SWG plates. I have to clean my plates way to often. So I really need to get the TA under control.

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Yes in the calculator it states to lower TA you reduce pH to 7.0-7.2 with acid and then aerate to increase pH.

5. ## Re: The Pool Calculator

Just checked my pH again and its now at 7.2 and the TA is still 250. But it took a lot more acid than 31 oz to get things to start moving downward. So by the instructions I should just let it aerate for awhile until the pH rises again, correct? maybe add a fountain to help a little? And incase you are wondering, my test kit is a TF-100.

6. ## Re: I am a little confused with the calculator

In your original question you said " The calculator is telling me to add 31oz of acid. 31oz is not going to drop my TA to 120."

We thought you were talking about using acid to lower TA without the necessary step of aeration. It's a matter of taking the pH down to the safe minimum and aerating as often as it takes to reach your goal of 120 TA.
That's why when using the calculator it's not saying to drop in the full amount of acid all at once as it can be damaging and the pool store should have warned you.

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You can be pretty creative with a trip to a hardware or big box store and some fittings. Build something that screws into a return

7. ## Re: The Pool Calculator

Originally Posted by Enkil810
Just checked my pH again and its now at 7.2 and the TA is still 250. But it took a lot more acid than 31 oz to get things to start moving downward. So by the instructions I should just let it aerate for awhile until the pH rises again, correct? maybe add a fountain to help a little? And incase you are wondering, my test kit is a TF-100.
Yes, you have to do this over and over again until you reach the TA you want. It takes a while, trust me I believe you. My TA likes to stay at 120-130 with my well water, and it's work to push the TA down. Unfortunately, it just takes time. You can't take the pH down far enough at a time without crashing it to a dangerously low level.

8. ## Re: I am a little confused with the calculator

Originally Posted by JasonLion
I am not sure what you were looking at, but the calculator doesn't have anything for calculating the amount of acid needed to lower the TA. You can't simply add acid to lower TA. If you did that you would lower the PH so much that it would damage the pool. Instead you need to follow the lowering TA procedure.
If you do some guess work in the effects of adding chemicals section with 31.45 MA and 10,500 gallons then you get 484 oz (3.78 gallons) of MA to lower TA by 180 ppm. It also states you would lower your pH by 11.07 which would probably melt your skin off if you did this in one step.

If you could let the pH rise to 7.8 and lower to 7.2 which is 0.6 difference then it would take about 18 or 19 times (11.07 / 0.6 = 18.45) before you got it down to 120 ppm. This is just guess work and may not hold up in the real world.

Also here is a formula for the total amount of acid to lower TA so many ppms.
http://www.poolgeniusnetwork.com/pro...emical-dosages
According to that it would take 15.12 quarts or 3.78 gallons to go from 300ppm TA to 120ppm TA which is what pool math shows.

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