I just watched TFP u-tube "pH and Total Alkalinity in your pool, what’s the big deal?" and....?

[calstar]

Due to medical issues I let my pool get out of control and want to get back on the right track. When I started the slam the pool was green with algae(pretty sure mustard) with FC 1 , CC 2, CYA of under 10, pH 8, CH 800(very hard public fill water), TA 130.

The common way to lower TA as I understand it is to drop pH to 7 (which lowers TA) then aerate to raise pH up while the TA remains low. I believe that Matt says(on the vid) that aeration only minimally raises pH, if that's the case how does one achieve a lower TA without taking an inordinate amount of time? I just finished slamming my pool today, passed overnight chlorine loss test, and added CH to 24 which pool math tells me is correct for a CYA of 40. My TA before slam was 130 and I want to lower it.
I also understood Matt to say adding CYA raises TA, I added 5lbs of CYA to reach 40, be interesting to see the TA level when the pH drops to normal levels, if high pH even makes a difference in the TA reading.

thanks in advance, Brian

 

[Diamond_Pool]

Lowering pH to 7 and aerating is the best way to bring Alkalinity down. Typically I leave it alone and let pH rise. When it hits around 7.8 I bring it down to 7.2 and repeat.

 

[JJ_Tex]

Generally speaking TA adjustments are more of a long term thing and as long as you focus on your pH your TA will naturally settle.

So in your case, watch pH and when it gets to 8, add enough acid to lower it to 7.2-7.4, which will also knock down your TA some. Eventually you will get your TA <100 and it will lessen the pH rise a bit.

 

[mknauss]

Realistically, at a CH of 800, it is time to drain and refill. Unless you do not mind calcium scale build up on your pool surfaces.

 

[mgtfp]

I haven't watched the whole video, but I reckon that what Matt meant was, that with active aeration you don't really speed up CO2 outgassing and the pH rise. You can just as well wait for CO2 outgassing happening all on it's own. Not much point in stressing out over thinking how to aerate the pool.

CYA Alkalinity is part of Total Alkalinity. But when adding CYA to the water, then it splits into various cyanurate ions, that are contributing to TA, and the same number of H+ ions, that count negative to TA. So when adding CYA, then there is no net increase in TA. You effectively replace Carbonate Alkalinity with CYA Alkalinity.

 

[Bperry]

Due to medical issues I let my pool get out of control and want to get back on the right track. When I started the slam the pool was green with algae(pretty sure mustard) with FC 1 , CC 2, CYA of under 10, pH 8, CH 800(very hard public fill water), TA 130.

The common way to lower TA as I understand it is to drop pH to 7 (which lowers TA) then aerate to raise pH up while the TA remains low. I believe that Matt says(on the vid) that aeration only minimally raises pH, if that's the case how does one achieve a lower TA without taking an inordinate amount of time? I just finished slamming my pool today, passed overnight chlorine loss test, and added CH to 24 which pool math tells me is correct for a CYA of 40. My TA before slam was 130 and I want to lower it.
I also understood Matt to say adding CYA raises TA, I added 5lbs of CYA to reach 40, be interesting to see the TA level when the pH drops to normal levels, if high pH even makes a difference in the TA reading.

thanks in advance, Brian

There’s really no need to mess with the TA. The only thing is does is buffer the pH so doesn’t rise too fast. If you just keep the pH in the 7’s, the TA will settle into its own level in time.

But if you’re in a SLAM, you shouldn’t bother with anything other than the pH and Chlorine.

 

[calstar]

Realistically, at a CH of 800, it is time to drain and refill. Unless you do not mind calcium scale build up on your pool surfaces.

My pool already has some scaling but in fact I do not mind. My CSI is always within the levels suggested with Pool Math, before slamming CSI was .29 with the suggested range being no lower than -.6 and no higher than .6. Draining and refilling is a pretty big deal in SoCal because of the prolonged drought conditions, it's hard for me to justify dumping the 14,000 gals. Before the rain we got this year in Santa Barbara our main water source, Lake Cachuma, was at about 10% of capacity, that is very daunting. As it is my pool is always covered, except when someone is in it, with a solar blanket to prevent as much evaporation as possible, very few people in my area have lawns to keep water use down.

thanks to all for the responses, Brian