High TA

[biggreydog]

I have a new pool in ground pool [plaster with quartz additive] , about 1 year old. Our water is extremely hard and alkaline. Chlorine is fine. pH always increases up to 7.8 each week despite my adding 2 gallons of 15% muriatic acid weekly. I have probably added 40 gallons of 15% muriatic acid over the last year. Total acid was about 240 and I am finally able to bring it down to about 150-160 [after 8 gallons of acid] but no further.

Is this from the plaster installation or from the initial pool fill water alkalinity or from some other issue? I have a cover on the pool, so I do not believe new autofill water is contributing to this.

Any suggestions how to bring this down once and for all so it doesn't keep creeping up?

 

[tim5055]

As your plaster cures you will continue to add acid to keep the pH in check. This will begin to slow during the curing process. I would say give the TA a little more time, it should come down as you continually adjust pH unless your autofill is adding high TA water. Have you tested four fill water?

 

[biggreydog]

How long should this process take? The autofill is running through a softener because of the extremely hard water in this area, though the pool was not initially filled in this manner. I wish the pool builder had told us how the plaster can raise the pH/TA like this. Would have helped. Getting some calcium deposit on floor, tile prematurely because of it.....

 

[JasonLion]

Plaster curing happens fairly rapidly for roughly the first month, and then much more slowly for roughly a year.

 

[ping]

If you want to use less acid overall, switch to full strength acid 31.45%. Most of the half strength acids sold cost just as much if not more than the full strength acid.

I would actively reduce the TA, Lowering Total Alkalinity, the lower TA will make the rise in pH slow down.

 

[biggreydog]

any recommendations for best place to get full strength acid? home depot here only as the 15%

 

[tim5055]

any recommendations for best place to get full strength acid? home depot here only as the 15%

do you have Lowes? They have both in the paint section. Green label is the "low fume" weak stuff, blue label is the good stuff. Ping is correct, they are both just about the same cost.

 

[Richard320]

Welcome!

I know where you live, even. My brother lives just down the road a bit in Atascadero, really close to the In-n-Out. I've been to Fourth of July in Templeton a couple times. Surreal.

 

[pooldv]

Lowes has 31.45% on the pool aisle near the garden section. HD probably does too.

 

[ping]

You can look in the paint section of the big box stores, that's where they keep the full strength stuff and they keep the 1/2 strength stuff with the pool supplies near me.