Do I need to adjust PH immediately after shocking my pool?
I shocked my pool with chlorine and noticed my acid dosing machine measured the pH at 8.8, though before the chlorine addition the pH was only 7.6.
Do I need to add acid immediately?
Thanks for the question Brad
If you used calcium hypochlorite, the granular form of chlorine, the pH will rise. Cal Hypo has a pH of 12 in and of itself.
If you're going to shock the pool it's best to use liquid chlorine. This won't raise the pH.
Be sure you're shocking the pool for the right reasons and not because you "should do it" once per week. Test the combined chlorine (CC). If it's above 0.6ppm then you should shock the pool but if not and all of your other readings are in line, there's no reason the shock on a weekly basis.
The chlorine, when kept between 1.5 - 3.5ppm and the CYA at 30 - 50ppm, will do its job through the week in killing off bacteria and organic matter.
You should try to reduce the pH as soon as possible, but at minimum after 2 - 3 hours after the shock. You don't want to be mixing chemicals. Allow some filtering before adding acid.
pH that is 8.0 - 8.2 is only allowing about 25% of the active chlorine so it's best to get the pH down. You can even shoot for 7.2. That's very acceptable, but I've always run my pools on my route and the the YMCA commercial pool at 7.6 - 7.8 with no problems at all.
At a pH of 7.6 - 7.8 you're still allowing about 45 - 50% active chlorination. Above 8.0 and it takes a nose-dive very quickly.
To post a reply, or if you have a similar question, you can see your post on the Q&A page in the "Shocking A Pool" category.
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Hope this helps.