The Pool Calculator

[CajunFoots]

Hi guys,

I have a fairly new pool. Gunite/Plaster, SWG, Ozone Generator My test kit is the LaMotte's ColorQ Pro 7. I really like it alot. It's easy to use and very similar to the Hach unit that we run cooling tower and boiler water samples at work. I also use the "Pool Calculator" (Great Program -- Thanks Jason).

My water chemistry is as folows: (12,000 gallon pool)

Free chlorine: 3.93
Total Chlorine: 3.94
pH: 7.9 (consistently)
Tot Alk.: 86
Calc. Hardness: 346
CYA: 79
Borates: 50 PPM
Salt: 3600 ppm
Pool Temp: 59 degrees F

According to the pool calculator's CSI (-.23 ), my water is balanced. However, if I lower the pH to 7.6, the Pool Calculator's CSI = (-.46) suggests there is a potential to become corrosive to plaster. The water is crystal clear and beautiful by the way. My question is, do I leave the pH at 7.9, or do I add muratic acid to lower it to 7.6 as recommended by "Pool School."

Thanks in advance,

Kevin Regira

 

[JasonLion]

The key question is how stable is your PH? If your PH really is stable, as you say, then it is alright to let it stay around 7.8 or even 7.9. The key point is that you don't want to allow PH to go up above 8.0. Many SWG users have fairly rapid PH rise and we recommend lowering the PH to 7.6 well before it gets above 8.0 so there is some room for mistakes. When PH is stable, that isn't really an issue.

With your numbers I would expect the PH to rise, but quite slowly. As long as you can be sure of lowering it before it gets above 8.0 you should be fine.