Since Evan sees firsthand F/G pools, I'd tend to take his advice first. In vinyl pools, I've seen t/a of 180 with no problems.

As for muriatic acid, "slow" usually means a cup to a quart pour VERY slowly into the return stream. Better still is to pour it SLOWLY into a 5 gallon bucket of water, then pour THAT into the return stream--less chance of stray acid reaching the pool wall.

3 gallons????!!!??? Maybe if your pH was 9.5 in a 48,000 gallon pool and you wanted to make it into an acid wash! Pool stores! Feh!


We believe in slow and gradual for all chemicals other than chlorine. If your pH is still in the 8's I'd add about 1/2 quart of muriatic acid and wait 12 hours, then check pH again. That's because you have 20K gallons and your pH is very high. Otherwise, I'd suggest half that--1 cup.