How fast does TA drop and pH raise?

[Aquatica]

I got an swg install in a pool I might or might not manage and want to drop TA down fast from 130 to 70-80.

The pool is 20,000 gallons and I know I need a little over 2 gallons of acid to get there. I know pH rises faster in SWG's pools.

Would like to get this pool balanced in a couple days. Just wondering if anyone has experience doing this? How fast would the pH go up until more acid could be added to get TA down?

I plan on adding 72oz - 75oz of MA at a time. pH will drop to 7.1-7.2 each time. Pool will be closed until balanced. of course as TA gets closer to 80 I'll use acid demand drop testing to get no lower than 7.2.

Thanks.

 

[Bama Rambler]

It all depends on how much aeration and outgassing you have. It's going to be hard for anybody to say how fast that will happen.

 

[Aquatica]

Thanks.

Tried it. added 75oz of MA and lowered TA from 150 to 120 and pH down to 7.2 in 30 mins.

added some more MA (100oz's) and will let the swg run overnight and check levels in the morning. seems to drop both TA and pH down in like 30 mins.

 

[Bama Rambler]

It drops pretty fast it's getting the pH back up to where you can lower it again that may or may not take a while.

 

[Aquatica]

It drops pretty fast it's getting the pH back up to where you can lower it again that may or may not take a while.

so true. might have to use some borax to get ph up tomorrow as owners coming on Saturday and would want to swim.

 

[chem geek]

If you add Borax, then that will raise the TA as well as the pH, though will only raise the TA half as much as pH Up product. Unless the pH is below 7.2, I wouldn't worry about it. The owners probably won't notice it and the pH will rise over time.

 

[Aquatica]

If you add Borax, then that will raise the TA as well as the pH, though will only raise the TA half as much as pH Up product. Unless the pH is below 7.2, I wouldn't worry about it. The owners probably won't notice it and the pH will rise over time.

Thanks Chem. Yeah trying not to use Borax. will see once pH is 7.2 at least I'll leave it. Looking for a TA of 80-90 tomorrow. Hopefully pH is up so I can drop it down to 7.2 then that's me done. just got to check salt level, turn on the heater..and I'm outta there. install and balance in 2 1/2 hrs...

 

[Aquatica]

well took 3 hours to install. had to jack hammer through steel reinforced concrete. some pics below.

TA is at 120 and pH at 7.2 so I left it as owners will be swimming tomorrow. all other levels are good. and water is looking much better..

 

[Locksmythe]

If you add Borax, then that will raise the TA as well as the pH, though will only raise the TA half as much as pH Up product. Unless the pH is below 7.2, I wouldn't worry about it. The owners probably won't notice it and the pH will rise over time.

I am trying to both lower TA and raise borates. I am switching to salt this year and never readded borax after the last 2 drain/refills for pool closings. TA is around 100-110, and Borates about 15. I have been trying to do the TA first with acid and aeration as Pool school encourages, but it seems that with this point of borax raising TA only half as much that there must be a faster way to accomplish both goals without having to wait so long for aeration. Thoughts?

 

[chem geek]

When I wrote that Borax raises TA half as much, I meant when it is used as a substitute for pH Up to raise the pH. When you add borax along with acid to increase borates but to keep the pH the same, then there is almost no rise in TA at all. 50 ppm Borates only increase TA by about 5 ppm at a pH of 7.5 and this rise isn't carbonates anyway do doesn't contribute at all to carbon dioxide outgassing.

If you want to lower the TA, then you can make that go faster by having the pH be low and aerating more since this increases the rate of carbon dioxide outgassing.

 

[msumoose]

Hey, is that a Compupool cell? I have a customer that has a bum Hayward cell and is considering it. Any thoughts?

 

[dschlic1]

I have a 7500 gal pool with "therapy" jets or a spa like action. When I lower the pH to 6.8 and use the jets to aerate in 10 hours the pH raises to about 7.2~7.3, not very fast at all. I would imagine on my pool to lower the TA from 120 to 70 would require cose to a week.