Liquid pH down (Sanygen) to reduce pH and alkalinity?

[LouiseT]

Hello all-I have a couple questions and need your expert advice please.

First…I had our Buckeye concrete pool (fiberglass sides) repainted 3 weeks ago. The alkalinity after filling was 350. I used liquid Sanygen pH down to reduce the alkalinity and then aerated to bring pH back up. The alkalinity is now at 160. The gentleman who did the painting said I needed to keep the alkalinity between 140-180 to prevent chalking of the epoxy paint. (I failed to ask if he meant for a particular time period or always…) I know that is quite a bit higher than recommended here. Any thoughts?

Second…the Sanygen pH down sold by the pool store is liquid sulfuric acid (photos below). I have seen the info here about preferences for muriatic acid vs dry acid and understand that sulfates can harm the SWG and concrete. I am no chemist…Does the same hold true for liquid sulfuric acid?Thanks in advance!

Current readiings (pool is sparkling!):
FC 5.5
pH 7.6
TA 160
CH 260
CYA 60
Salt 3400

 

[mknauss]

Sulfuric acid adds sulfates. Do NOT use.

You will drive yourself crazy holding a TA that high. That will have no bearing on the paint, it will last a year or two at most regardless.

 

[JamesW]

The gentleman who did the painting said I needed to keep the alkalinity between 140-180 to prevent chalking of the epoxy paint.

It's going to chalk regardless of what the chemistry is.