Low PH -- High Alkalinity

[CarlD]

Much ado about nothing!

As usual, the pool store cretin has NO idea what he's talking about.

1) Muriatic acid is fine but you do have to be careful adding it. I like to dilute it in a 5 gallon bucket first, and never use more than 1 quart at a time.

2) You have a vinyl pool If the acid collects on the liner it starts to melt it. Bad, very bad.

3) Normal T/A range is supposed to be 80-125ppm. HOWEVER: with a vinyl pool you can safely allow it to go to 180 without ANY problems.

4) For swimming, pH of 7.2 is still safe for swimming and T/A of 170 is fine.

5) For closing, I like to see higher pH--around 7.6. Lots of places have acid rain (like NJ where I live). But if you raise pH, TA will go up to...UNLESS...

6) You go find the method for lowering T/A here:
a.Lower you pH to 7.0 to 7.2, no higher, no lower.
b.Aerate your water. You can just leave it uncovered with the pump on, or speed it up with a gang of 12 year olds, a fountain, or a screw in sprayer (this replaces your eyeball in your return and is about 20 bucks.
c. pH should rise without T/A rising.
d. Add acid again to drop pH to 7.0-7.2
e. Aerate again.
f. When T/A is where you want it (say, 125 for your pool), aerate to raise pH, then add Borax (NOT Soda Ash!) to raise it further. T/A will go up a little with the Borax, but that's OK. The Soda Ash, instead, will undo all your good work.

Or you can just use Borax to raise your pH. T/A will rise with it, but if it's below 180, don't worry, just close. If it's below 200, you can either lower T/A or just go ahead and close. Over 200, it's easy to get white cloudy water, so I like 180 as the safety margin below that.

Still, if the water goes WHITE and cloudy from too high TA over the winter it's not a tough fix--it's not algae growing--and just adding acid in the spring should clear it.

Just my take.

[chem geek]

Thanks Carl. I missed the part about this being a vinyl pool. As you said, the TA level is no problem in this case except possibly causing a greater tendency for upward pH drift (or greater use of acid to keep pH lower).

Richard