Dead Acid ?!?

Sentinal69 · May 28, 2021

10,000 gal pool fiberglass and plaster, TA 130, CH 100, ph 7.2, Temp 80. Problem - Monday started out with TA at 280 (Well water). After 1 gal acid TA came down to 205. After 2 gal of acid, TA came down to 160. Added a qt of metal out and another gal of acid - TA is now 130 !
On a 10000 gal pool and 3 gal of acid, my TA should be less than zero !!
I acid washed the brown grit off the entire pool and filled with fresh water - installed a new pump and new cartridge filter. Then started this process - am getting freaked out by all the acid I’m using ... help ?!?!
Acid is Muriatic from Menards - 31.45 HCl 20 Baume

JamesW · May 28, 2021

Each gallon of acid will lower the TA by 50 ppm.

280 - 150 = 130.

You should use PoolMath to lower the pH to 7.2.

You are probably being too aggressive on adding acid.

Sentinal69 · May 29, 2021

JamesW said:
Each gallon of acid will lower the TA by 50 ppm.

280 - 150 = 130.

You should use PoolMath to lower the pH to 7.2.

You are probably being too aggressive on adding acid.

Well that explains much !! I was told a gallon of acid would drop the TA by 100 in my pool - the 50 number makes everything make sense and I’m on the right track ! 1 more gallon and I’ll be ready

. Thanks

JamesW · May 29, 2021

Don't drop the pH below 7.2.

Sentinal69 · May 29, 2021

JamesW said:
Don't drop the pH below 7.2.

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Lower Total Alkalinity

A lower Total Alkalinity level can help a pool owner stabalize their pH increase. We'll explain how to lower TA with a little help from muriatic acid.

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It’s not low for long -

JamesW · May 29, 2021

Ok, but going below 7.0 can begin to damage any metals like copper.

In any case, there really is no reason to try to force it down at an accelerated pace.