My pool seems to insist on a low TA

[frankc29]

First some info on my pool. It's inground, pebbletech finish, salt water chlorinated, with attached spa. My latest numbers are:

FC - 5
CC - 0
Cya - 40
PH - 7.4-7.6
TA - 50
Cal - 300
Salt - 2900 ppm
Temp - 85

I've had this pool for about 4 years, I change the water every 2 years. For the longest time I fought to maintain a TA of 80-120. This required my adding a 12 lb bag of baking soda every couple of months or so. Over those 2 months the TA would slowly go from 120 to 60. I also needed to add about 2-3 quarts of acid per week to maintain Ph in the 7.2-7.4 range, the strong acid, not the half strength stuff they sell now in some places. I noticed though that when my TA is low I dont need to add acid nearly as often. With the TA at 50 now, I have gone almost a month without having to add acid, it's always around 7.4-7.6. In essence I feel that my pool is telling me to quit adding baking soda, it likes a TA in the very low range, thank you very much. Should I leave it be?

 

[duraleigh]

In essence I feel that my pool is telling me to quit adding baking soda, it likes a TA in the very low range, thank you very much.

Cha-Ching! :lol: Leave your pool where it is happy as long as you are withinn reasonable guidelines (you are)

 

[frustratedpoolmom]

Off topic but why do you change the water every 2 years? Unneccessary IMHO

 

[itstoohot]

This topic seemed similar enough, so I am going to further it with another question. For the previous two years on the BBB, I would add liquid chlorine (12%) to maintain FC. This would cause PH to creep up and I would be adding acid at least once every two weeks. Alkalinity was typically in the 120 range and I would add baking soda to keep it there. For reasons unknown, I let the TA drop to about 90 at the end of last year. It was 80 when I opened it and it has progressively decreased to its current level of 50. Now for the interesting part - I didn't use much more than 24 oz of acid all season to keep PH in line, while continuing to use about the same amount of chlorine.

Anyone see a problem leaving TA at this level? It works for me, but I don't want to cause undue damage to the pool out of ignorance. I am getting ready to close for the season and have been debating increasing the TA to 70 - 80.

Thanks for your advice!

 

[polyvue]

I let the TA drop to about 90 at the end of last year. It was 80 when I opened it and it has progressively decreased to its current level of 50. Anyone see a problem leaving TA at this level?

I think it depends somewhat on your other parameters, especially Calcium Hardness and pH. Try entering your numbers into the Pool Calculator to be sure that your water is balanced.


See also pool-school/recommended_levels

Vinyl with Bleach

FC 3-7
pH 7.5-7.8
TA 70-90+
CH 50-300
CYA 30-50

with SWG

FC 3-5
pH 7.5-7.8
TA 60-80
CH 50-300
CYA 70-80

 

[frustratedpoolmom]

If the PH is stable with a TA of 50 then don't worry about it. Sometimes low TA can cause drastic swings in PH levels.

 

[duraleigh]

For the previous two years on the BBB, I would add liquid chlorine (12%) to maintain FC. This would cause PH to creep up and I would be adding acid at least once every two weeks.

Just to clarify, many (most) pools have a natural tendency for pH rise but it's not from using liquid chlorine. While there is a temporary rise when you add liquid chlorine, the process it goes thru when it's in your pool results in virtually no long term affect on your pH. :lol:

 

[itstoohot]

It has been a rather wet summer in our area (South Central PA). I wonder how much that contributed to keeping the PH in check? Also, if liquid chlorine does not cause the PH to rise, what does? The only things I ever add to the pool are liquid chlorine and muriatic acid.