Boric Acid affect on pH; Is this OK?

[JimK]

We've had alot of rain the past couple weeks and have had to pump water out of the pool several times, so I knew I needed to test everything to see what needed adjusting. Here's the results prior to making any adjustments:

pH 7.6 (it's been stable at 7.6 since mid June)
FC 5 (I keep it at 5-6)
CC 0 (except for spring cleanup, its always 0)
TA 80 (last I checked before all the rains and pumping water out it was at 100)
CYA 50 (was 80 before all the rains/pumping)
borate 40 (was 60 before all the rains/pumping)
Salt 3000 (I had already added 80# of salt a couple days before since I already knew it was low)

I added 5# of CYA to bring CYA back up to 80 and added 19# of boric acid (per The Pool Calculator) to bring borates back up to 60. This is the first time I've used boric acid. Previously I was using tetraborate pentahydrate but figured I'd switch to boric acid (purchased from The Chemstry Store mentioned here) so I wouldn't have to deal with adding muriatic acid.

I read here that boric acid is slightly acidic and would have a small effect on pH. An hour after adding the boric acid (broadcast throughout pool and brushed to dissolve any that settled on bottom) I checked the pH again and was surprised to see it had dropped to 7.2.

I didn't expect it to drop that much. Is this much of a drop normal for the amount I added? Anything I should be concerned about with such an abrupt pH change? Is there an effect on TA and should I retest/keep an eye on TA as the pH goes back up (I use a SWCG so I expect the pH will rise on it's own)? Anything else it may have altered I need to recheck?

Thanks.:)

[waterbear]

Don't worry about it , the pH will rise on its own as CO2 slowly gasses off. 7.2 is well within normal operating parameters. If you want to raise it faster aerate the water but DO NOT add a chemial to raise pH (unless you want to add some borax)
However, as I said, just leave ti alone and don't lose any sleep over it.

[JimK]

Don't worry about it , the pH will rise on its own as CO2 slowly gasses off. 7.2 is well within normal operating parameters. If you want to raise it faster aerate the water but DO NOT add a chemial to raise pH (unless you want to add some borax)
However, as I said, just leave it alone and don't lose any sleep over it.

Thanks for the feedback and reassurance.

Since pH is still "normal", I'll just leave it alone as it will rise on its own due to the SWCG.

As aeration from the SWCG raises the pH will TA drop?

[waterbear]

No, the act of adding acid makes TA drop since it converts bicarbonate to carbon dioxide which then gases off. Aeration raises pH with no effect on TA. Borate does add to TA so even though you have removed some bicarbonate by adding the boric acid you have replaced it with borate, which is still measured as TA

[JimK]

No, the act of adding acid makes TA drop since it converts bicarbonate to carbon dioxide which then gases off. Aeration raises pH with no effect on TA. Borate does add to TA so even though you have removed some bicarbonate by adding the boric acid you have replaced it with borate, which is still measured as TA

Thanks for the explanation. The TA reading in my post was before adding boric acid. Out of curiosity, I'll check it again to see what TA now reads.

sigh........looks like we may be in for more flooding rains this weekend.:mad: