I know I shouldn't close my pool with the pH low, but will it hurt to close with it high? I've put a couple of gallons of muriatic acid in and aerated to get my TA down to 120 in the last 2 weeks, but the pH drifted back up to 8.2 from 7.8 when I put my maintenance dose of chlorine in. My water temp is down to 62 and I'm ready to close. Will the pH go even higher when I shock? Can I deal with this pH problem when I open in the spring?
close with pH high
- Thread starter robfletch
- Start date
- Jun 22, 2014
- 47,722
- Pool Size
- 17888
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-45 Plus
Ideally you do want the pH adjusted to about 7.5-7.8 at closing. Remember too that when you dose your pool with more chlorine (FC over 10) you will get a false (high) pH reading, perhaps that's throwing-off your test result a bit? pH can rise slightly in the winter months. Higher pH could lead to scaling, although that shouldn't be a big issue for your type pool, but still not ideal. The fact that your TA is still at 120 could also be pulling your pH up with it which indicates you could still lower the TA some more. Since your water temp is still over 60, I wouldn't close the pool until you know for sure the water will remain below 60. So you may still have a few days where you can adjust the TA and pH down to remain more constant. In the end, just make sure the FC is below 10 when you test the pH. Next spring you'll test all your chemical levels and start fresh next season. Hope this helps.
My FC was 1.5, CC-.5, pH-7.8 before I put my maintenance dose of chlorine in. I was aiming for FC of 5 and got 6.5. Do you think the maintenance dose (140 ounces 10.5 chlorine) caused the pH rise? I guess I'll know the answer to that if it doesn't drop in the next couple of days.
- Jun 22, 2014
- 47,722
- Pool Size
- 17888
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-45 Plus
In that case, no. Your FC was low enough to not skew the pH test. I would continue with the lowering of the TA if possible which will help to keep your pH more constant. Even if you only get it down to about 80-100 before closing, that should help more than the current 120. Also, be very careful about the FC getting too low on any given day. I know you're about to close, but you never want it that low (1.5). The last thing you want to do just before closing is to have to deal with an algae bloom. 
Just as a reminder ... since I don't know your current CYA level, I have no idea what your FC really should be on a regular day or at SLAM level for closing, but you'll definitely want to ensure you are matching them up (FC and CYA) as noted on the Pool School - Chlorine / CYA Chart. That's very important. If you have any more questions, please let us know. Good luck!
Just as a reminder ... since I don't know your current CYA level, I have no idea what your FC really should be on a regular day or at SLAM level for closing, but you'll definitely want to ensure you are matching them up (FC and CYA) as noted on the Pool School - Chlorine / CYA Chart. That's very important. If you have any more questions, please let us know. Good luck!
- Jun 22, 2014
- 47,722
- Pool Size
- 17888
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-45 Plus
Oh, okay. In that case, when you do actually go to close, make sure you take the FC up to 16 and let it mix for 24 hours before shutting the pool down. Have a nice day.
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