Chemical levels for closing

[mike.stocker]

Howdy TFP, question on chemical levels for closing my pool. Below are my most recent test results. I’ve had a low level algae issue so have been SLAMing the pool recently, that’s why the chlorine is high. The pool is crystal clear otherwise, just what appears to be dead algae on the floor in the same spots each morning. Regardless, which of these, if any, should I manipulate before closing? I read I should close at SLAM levels of FC so I think I am good there. Should I mess with the pH or CYA levels at all? My CYA is low so wondering about that one in particular. I just haven’t bothered to bring it back up lately as it’s been cold and I’m not losing much chlorine on a daily basis.

Also, I am having a safety cover installed next week. Anything special I need to do to maintain the pool over the winter with that type of cover? I’m a little worried about leaves and debris seeping through and causing issues but hopefully if I keep it relatively clean, it’ll be fine. I do plan on adding some algaecide before closing as a preventative measure.

Thanks in advance!

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39W

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Build Type: Vinyl

Volume: 25178 gallons

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Latest Test Result Summary:

FC: 12.0 (24 minutes ago)

CC: 0.0 (24 minutes ago)

pH: 7.6 (24 minutes ago)

TA: 90 (24 minutes ago)

CH: 225 (24 minutes ago)

CYA: 20 (24 minutes ago)

TEMPERATURE: 57° (24 minutes ago)

CSI: -0.30 (24 minutes ago)

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[Texas Splash]

I would get one more CYA test tomorrow if you have a nice sunny day for optimal viewing. Closing at 20 could leave you with no CYA by spring and that could cause issues. If it is low, I would take it up to at least 30, maybe even 40 would be fine.

 

[Newdude]

I do plan on adding some algaecide before closing as a preventative measure.

Algecide and FC battle it out and you're left with less of each, so when using Polyquat, the rec is for half SLAM. If you don't have enough time to let the FC fall, then just skip the PQ.

I’m a little worried about leaves and debris

Leaves and debris blow under either safety cover, and it's not a problem. Open while it's still cool, get the debris out, and you'll be fine.

 

[Mdragger88]

Also, the ph test is invalid at fc levels above 10ppm (usually reads higher) so don’t worry about that. Its likely still mid 7’s which is A-ok
In doing the
SLAM Process you’re supposed to keep going until all 3 are true-
CC is 0.5 or lower;
You pass an Overnight Chlorine Loss Test
AND
The water is clear.
(Crystal Clear w/no algae dead or alive)

 

[mike.stocker]

Thanks all! Great information as always.