Adjust pH up after Acid Start

[scarob63]

This pool is 3 months old.

I did acid start again after poor install. Pool surface is substantially improved. I want to bring pH back up after adding 5.25 gal of MA (3.5 gal./10,000 gal.). I read somewhere here to ad pH up at the rate of 1 lb. per quart of acid or 21 lbs. I want to make sure this is right before I proceed to raise pH in a few days.

 

[JasonLion]

There isn't any specific amount of PH Up to use. Some of the acid will have been neutralized as it acted on the plaster. Just how much was neutralized reacting with plaster and how much remains to be neutralized with PH Up is impossible to determine exactly. 21 lbs total is a good guess, but it is only approximate. I suggest adding perhaps two thirds that much to start with, give it an hour to mixing, retest to see where you got, and then adjust with 4 lbs at a time from there until the PH comes up above 7.0. It is a little more work this way, but saves you trouble latter if you accidentally overshoot and got the PH too high.

 

[scarob63]

Thanks. Right now the pH is to low to measure with a base demand test, I added 40 drops with no color change.

 

[JasonLion]

If you have an acid demand test, you can use the table that comes with to calculate the amount of chemical to add. It is still a good idea to add perhaps 2/3rds as much as you get that way, but it will be a better starting point than the rough estimates above.