2 months in, number seem right?

nitz369

Well-known member
Mar 22, 2008
83
Okay I have been doing the Bleach and Acid thing for a couple of months now and there is a good trend going on.
I just want to make sure the trend seems right to everyone else.

Trend:
2-3ppm chlorine loss per day, pool gets 8 good hours of sun in Vegas
pH increases from 7.6 to 8.2 within a couple days, adding 20-25oz of Acid for 12,000g pool.

Other numbers:
CYA checked a month ago was about 50 (do you go until you can't see the dot at all?)
TA: was 140, tested yesterday, down to 100, must be fill water because pool is autofill.

So does the trend make sense? Seems like lots of Acid is being used. Is it true that Bleach will raise pH level because it is unstablized? whereas granulated chlorine "shock" doesn't?
 

JasonLion

TFP Expert
Platinum Supporter
LifeTime Supporter
May 7, 2007
37,879
Silver Spring, MD
There are two reasons that PH tends to constantly go up, one is high TA and aeration the other is fresh plaster. Your TA was quite high and is still somewhat high so if you have a source of aeration, fountain/waterfall/rain/SWG, that could account for some/all of the PH rise. With bleach you can let the TA continue to go down to the 70 to 80 range and that will reduce the PH increase to some extent. You don't say if you have fresh plaster. Plaster raises PH, TA, and CH rapidly for about three weeks and then more slowly for up to a year. Usually after the first several week all you notice is the PH increase.

It is the acid which is bringing the TA down. Acid lowers PH a lot and TA a little.

Bleach has no detectable long term effect on PH. Granular shock is usually dichlor, which will is acidic and will reduce PH. Powdered shock is usually cal-hypo which, like bleach, has little long term effect on PH. Every now and then you see granular trichlor, which will also reduce the PH, though not by as much as dichlor does.

It would be nice if you could put some basic specs for your pool and equipment in your signature. That will help up answer your questions more easily and throughly.