TA, PH & Aeration

[Sidecarist]

I am getting ready to add Borates to my pool. I would also like to lower my TA a bit more as part of the process. I am concerned that the addition of a working SWG will cause my PH to rise more quickly than I want.

I know that adding the Borax will raise the TA as well currently I'm at a TA of 80 and I'm thinking I want to be about 60 but that's just a guess. I've added a new SWG this year and I'm learning about how it changes PH on the fly... but only have a couple of weeks so far. Water is still cold, but the Solar heater is bringing it up to swimming temp slowly.

I have a spa jet that fits into a return that I can use for aeration. Pool math tells me that reducing the PH from 7.6 to 7.0 will lower the TA by 11. I'll have to do that twice to hit my goal of 60+/-.

The question I have is does anyone know how long will it take to get the PH back up from 7.0 to 7.6 using the spa jet. It creates a nice small bubble plume in the pool so I'm hopeful the process won't be long.

I'm not looking for hard and fast numbers but more of an approximation from experience. Am I looking at a 2 day process, 10 days, ??? days?

Current numbers are

FC 6
CC 0
TA 80
CH 220
CYA 60
Borates 0
SALT 4000

PH 7.6
Temp 72degF

Thanks.

 

[JVTrain]

You should lower your TA to 60 before starting to add borates. Using your spa aerator I would say about 2-3 days with your approach but it's highly dependent on a few things including the amount of bubbles produced and your pool volume. If you can angle your pool returns toward the surface as well, that will create some additional aeration.

 

[Sidecarist]

Ok, thanks. This gives me a ball park to work with. I plan on lowering the TA to 60 before adding the Borates, then when that process is complete adjusting it to 60 as my goal. It will take some time, but is doable in a couple of weeks keeping an eye on it in the morning and evening.

I'll be watching the PH to make sure that I don't get a PH crash from lowering TA too far as well. I hope to find a good balance point. and with the buffering effects of the borates make my PH as stable as possible.

Thanks again.

 

[Jimrahbe]

What works best for me is to drop the pH with acid to 7.0 and then immediately aerate. The key is to check the pH again in three or four hours, then add acid again to bring it back to 7.0.. and keep repeating until you get the TA down to a little less than you want. Then quit adding acid and aerate until the pH comes back up to 7.5 or so. I do this routine on three pools in the DFW area. They all have SWGs, but no constant water features. I do not use Borates and my pH will stay between 7.5 and 7.8 for several months in a row before I have to do the process again. The process takes me less the two days most of the time. When I tried to do this with longer periods between acid additions, it seemed to take several days to a week.

Jim R.

I use this to aerate..

 

[Sidecarist]

Interesting. I read in another post that the lower the PH the faster the TA reduction. That matches with your results. I'll be able to dedicate a full weekend to it in a couple of weeks so I'll wait till then, make sure that I have enough acid on hand and give it a try.

Thanks!