Help with high TA in spa

[KrisIL]

Split by moderator from HERE. jblizzle

Is it okay if I measured the pH , CH and TA while water was cold? About 50F? Or should I heat the water to about 100F and then measure again?
What I got now is:
pH - 7.8
CH - 30
TA - 420.
So now I just concentrate on TA. I need to lower pH to 7.0 using muriatic acid purchased from Home Depot and then aerate till it get to pH 7.8 . Check TA again and use poolcalculator to check how much muriatic acid I need to add right now.
Do you suggest to check the pH level after 1 hour of aerating?

 

[chem geek]

Re: How do I use Chlorine in my Spa (or pool)?

Cold is fine. It will take longer for aeration to raise the pH, but the procedure will still work. Yes, you should get your TA lowered at least somewhat or else you'll be fighting rising pH. 1 hour of aerating should be plenty, but you can just check after 30 minutes to see how much the pH is risen. It should rise pretty fast given your high TA. It will rise more slowly when the TA gets lower. It also rises most quickly when the pH is low (i.e. at 7.0 that you will initially lower).

 

[KrisIL]

Re: How do I use Chlorine in my Spa (or pool)?

Is it okay to lower pH as soon as it rises to about 7.4? Or it's better to wait til it go to about 7.8?

 

[chem geek]

Re: How do I use Chlorine in my Spa (or pool)?

It goes faster if you keep the pH lower so as soon as you see it rise you lower it. The rate of carbon dioxide outgassing is faster at lower pH. You can see this effect by seeing how much over-carbonation there is of carbon dioxide in water vs. air at various TA and pH levels in this chart.

 

[KrisIL]

Re: How do I use Chlorine in my Spa (or pool)?

Okay. I will stay by the tub all afternoon to lower the TA