Correcting high TA, PH OK

[Buggsw]

I'm trying to lower my TA from 140 down to below 120 using muriatic acid. So far it seems to be working well. Last night and this morning my TA is 125 today with a ph of 7.2

I added a little more acid this morning and hopefully my TA will then be below 120 by this evening when I get home.


I'm a little surprised that my ph stayed at 7.2 because I ran the aerator all night - I thought that was supposed to raise ph. So, I would expect that this evening my ph may be too low and will want to raise it.

I read that I should use 20 Mule Team Borax - but I don't know what proportions to add it. A cup? A box?




I have an IG, plaster, 12K, with a Sand/Zeolite filter.

 

[chem geek]

Don't use Borax or any other pH raising product (for this TA lowering procedure). Once you have the TA at the level that you want, just aerate to get the pH to rise. The fact that aeration wasn't working for you is strange and either means that the source of aeration isn't strong enough or you have some other source of acid in your pool (such as Trichlor or non-chlorine shock).

 

[Buggsw]

Okay, so just keep trying with the aeration then? Seems the aeration is pretty powerful, actually, to me. I used Leslie's Chlor Brite to shock this weekend, which I believe is di-chlor - not at home to read the pkg.

 

[chem geek]

Yes, Leslie's Chlor Brite is Dichlor (dihydrate) and for every 1 ppm of Free Chlorine (FC) you added with this shock, you also added 0.9 ppm Cyanuric Acid (CYA) as well. Is that what you wanted to do? Was your CYA level low? If not, then you should not use Trichlor nor Dichlor products. Only use those when you want to raise your CYA.

And Dichlor is acidic, not pH neutral as claimed. The reason is that though the addition of Dichlor is initially close to pH neutral (it's very slightly acidic), the consumption of chlorine through its breakdown from sunlight or its oxidation of organics or ammonia or killing bacteria and algae are all acidic processes. So the net result is acidic. That probably explains why you didn't see the pH rise. As the FC level dropped, the pH dropped as well and the aeration raised it so the net result saw no change in pH. Once the FC is stable, then the aeration should make the pH rise more readily.

Why do you think the aeration is powerful? What is it you are using for the aeration? The most powerful aeration is using an air compressor with a nozzle that produces tiny bubbles and putting the nozzle end into the deep end of the pool. Fountains, waterfalls, spillovers, pointing jets upwards, etc. are also good techniques and of course the pool should remain uncovered during the entire time you are aerating.

 

[Buggsw]

Thanks so much for all the info about the Chlor Brite. I will check my CYA again, tonight.

I have a built in aerator on the side of my pool. It sprays the water up into the air at a good force so like a spray fountain, I guess.
So while the force of spray is strong, it may not be strong as in aeration??

My returns are the infloor cleaning system (10 toe stubbers) - 2 at a time are in use and are pretty powerful.

Pool is always uncovered.

 

[chem geek]

If the spray fans out into lots of little droplets, then that's good aeration. Let's just see what happens going forward. I suspect you just saw the results of using the Dichlor and having the FC drop back down to normal. Keep aerating.

 

[Buggsw]

Will do. Yes, it fans out quite a large/wide spray. Thanks so much for your help.