Keeping pH in check with low Total Alkalinity

[HofstraJet]

I started maintaining my own pool using the BBB method a few months ago when we fired our pool guy and the pool has never looked better. My problem is rising pH, likely due to the spa overflowing into the pool. Here are this morning's numbers:

FC: 2
CC: 0
pH: 7.4
TA: 50
CH: 250
CYA: 40
Borates: 50
Water temp: 86 F

I keep a floater with a trichlor puck in the pool to maintain chlorine levels. It is just me and my wife and we swim on the weekends, so the pool sees no use during the week. We live in S Florida and the afternoon thundershowers fill the pool regularly, which I drain to maintain an appropriate level, so there is a lot of new rain water being added regularly. The pH always seemed to rise when I had my Total Alkalinity at 80-100. and I was adding a lot of acid. I recently lowered TA to 40 and it rose to 50 in the past few days, I assume due to rain water. According to the Pool Calculator, my CSI is -0.48, not lower than -0.6, but close. Just want to be sure I am on the right path to keeping my pH in check. Obviously I will continue monitoring the TA for the next few weeks and see if it goes back up. Thanks!

 

[susa]

At some point the trichlor will overpower the CYA level so you will have to make changes. Some people on the forum use automation, myself included, to maintain the pH. In my case I simply swap out a new muriatic acid bottle from home depot about every 2.5 weeks and dial the control to desired setting.

 

[JasonLion]

Yes, it sounds like you are on the right path. Between the lower TA, and the trichlor tablets, you shouldn't have any more problems with the PH drifting up. If anything, there is a risk that your PH might tend to go down now given the trichlor tablets.

 

[lightingguy]

You may find your PH is more stable at a higher level. Most of us assume that if PH rises from 7.2 to 7.6 in a week it will go to 8.0 the next week. This isn't necessarily true.

Since you are using Trichlor (which is acidic) and have lowered the TA it sounds like you have a lot of aeration. Any way to cut the amount of time the spa spill over runs?

 

[duraleigh]

You may find your PH is more stable at a higher level. Most of us assume that if PH rises from 7.2 to 7.6 in a week it will go to 8.0 the next week. This isn't necessarily true.

lightningguy brings up an excellent point that I would like to emphasize. Many non-SWG pools seems to find a sweet spot for pH and stabilize. Mine seems to like 7.8 for quite a long time before it goes on up to 8.0 and then I bring it down to 7.3-7.4.

You won't hurt your pool a bit if you let it go on up to see if it can find that sweet spot....just monitor it carefully when it gets close to 8.0