PH Consistently 8+ in a Small Gunite Michigan Indoor Pool

[drdamour]

Regarding alkalinity, don't try to raise it, till you have pH, and hardness results as WELL as TA (total alkalinity) results.

darn, too late, i did it this morning, does this alter your recommendations?
IS there an order to adding the chlorine and acid? do they need to be done 24 hours apart or anything?
Can you fill me in on the math behind the amounts you've suggested?

[PoolDoc]

Put bleach in the skimmer and acid in your pool, and you can do them both at the same time WITH THE PUMP RUNNING!

Chlorine math: 120,000 gal = ~ 1,000,000# water; 120/5 = pool factor of 24; 6% bleach => 8.6# x 0.06 = ~0.5 lbs Cl2 equiv; 24 x 0.5 = 12 ppm; 12/4 (1/4 gal) = 3 ppm

Acid math: seat of the pants. pH calcs are hard, even if you have accurate TA values, accurate knowledge of the various buffers present (polyprotic acids) and accurate initial pH values. Conservative seat of the pants measurements work OK.

Adding sodium bicarb now just means more acid later.

[CarlD]

Ben,
We haven't seen a CYA result. I know CYA should not be used in indoor pools, but drdamour put in some sort of powdered chlorine. If it wasn't cal-hypo....there's now a CYA presence...

More Chlorine Math:
FC desired (in ppm) = (1,000,000/pool gallons) * (.06) * num gallons. Since your pool is 5,000 gallons, and you want an FC increase of 3ppm, that's 1/4 gallon. .06 is the concentration of 6% bleach (6%=.06)
I can do THAT in my head since I know that 1 gallon of 6% adds 6ppm to 10,000 gallons. Since you have half that, 1/2 gallon gets the same 6ppm increase. Since you only want half of 6ppm, that's 1/4 gallon=1 quart of bleach.

Carl