Pool Closing, what should chlorine be when I put on the cover?

MeAndJulio

Member
Jul 7, 2019
16
Northern Neck, Virginia
Surface
Vinyl
Chlorine
Liquid Chlorine
I need to close my pool by Friday night; we ask friends to help get the cover on and I need to ask them in advance.
I am confused (about a SLAM) as I read through many posts.
Here's my situation, I'd like some advice.
This summer the chlorine numbers have stayed stable. The time I did a one-night SLAM, it held the OCLT but it took several days to get the chlorine down.
Here are my questions:
1. Do I need to do a SLAM before closing? Or can I bring it up to FC: 5 and put on the cover the next day?
2. What should the CL be when I put on the cover (woven solid cover, with water bags)? My real concern is weakening/damaging the cover (happened in the past) when the CL is too high.
3. I usually use Polyquat60. I read that the CL should not be high when it is added. What is too high?
Thank you!
Test data tonight:
FC: 2.0
CC: 0
ph: 7.5
TA: 95
CA: 9 (vinyl)
CYA: 35
IG 20K vinyl liner, use liquid chlorine
 
Seems a bit early - and too warm - to close.
If you can't do it after the water temp is consistently below 60 degrees:

Do an Overnight Chlorine Loss Test to rule out any possible algae issues. SLAM if necessary.
Bring FC up to SLAM level for your CYA and run the pump for 15 minutes or more.
Drain down, blow the lines and cover.
 
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I need to close my pool by Friday night; we ask friends to help get the cover on and I need to ask them in advance.
I am confused (about a SLAM) as I read through many posts.
Here's my situation, I'd like some advice.
This summer the chlorine numbers have stayed stable. The time I did a one-night SLAM, it held the OCLT but it took several days to get the chlorine down.
Here are my questions:
1. Do I need to do a SLAM before closing? Or can I bring it up to FC: 5 and put on the cover the next day?
2. What should the CL be when I put on the cover (woven solid cover, with water bags)? My real concern is weakening/damaging the cover (happened in the past) when the CL is too high.
3. I usually use Polyquat60. I read that the CL should not be high when it is added. What is too high?
Thank you!
Test data tonight:
FC: 2.0
CC: 0
ph: 7.5
TA: 95
CA: 9 (vinyl)
CYA: 35
IG 20K vinyl liner, use liquid chlorine
I’ve never heard of a one night SLAM, but I suppose it’s possible. Are you sure the three exit criteria were checked off before stopping? Or was that a preventative maintainance kinda thing?

Your FC is already too low and water too warm. I’d recommend getting your chlorine back up to a normal 5-7 and do another OCLT to make sure you aren’t in algae mode.
 
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3. I usually use Polyquat60. I read that the CL should not be high when it is added. What is too high?

Read Algaecide - Further Reading about PQ60.

FC at half SLAM level or below is fine for PQ60.

With a CYA of 40 I would get your FC to around 8 for the close.

It is up to you if you want to raise your FC to SLAM level of 16 for a while before close. Can't hurt.
 
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I appreciate everyone taking the time to answer my questions!
For #2 about the chlorine level before covering the pool: I talked to the Pool Store, who advised keeping the FC below 10 before adding a cover. Info provided in case others are interested.
Pool is all chlorinated, polyquated, covered, and put to sleep this evening! Thanks.
 
The pool store advice is based upon a CYA level of "0" (zero).
With CYA of 30-40 buffering the chlorine, a higher FC than 10 is fine.
 
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Fwiw- I close at slam level for my cya every year. (This is usually 28-31 ppm fc).
I usually open with fc still above 10ppm in the spring.
My first cheapo tarp style solid cover lasted 3 winters.
This one is going on winter #2.
Most people are lucky if the tarp ones make it past 1 winter before tearing/ripping & it’s generally recommended to just get a new one each year because no matter what they claim they just don’t last no matter the fc level.
Don’t be afraid of adequate fc levels- its what keeps you from having a swamp.
 
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