Chlorine level at closing

tolian21

Member
Mar 27, 2019
23
NJ
Why shock level is recommended for closing?
If you have solid pool cover the high clorine level is bad for the cover and will shorten its life. If you add algecide and closing in colder temperature, it will be ok without shock level, no alge will grow
 

JimMarshall

Gold Supporter
TFP Guide
Jun 5, 2017
725
Oil City PA
What makes you think that SLAM levels are going to harm your cover?

It is recommended to bring to SLAM level and hold for 24 hours to ensure that there are no organics in your pool to multiply while it's closed
 

tolian21

Member
Mar 27, 2019
23
NJ
Solid covers deteriorate faster and become more brittle from high levels of chlorine. If you’ve been maitaining proper chlorine levels, I dont see why you should have bacteria growing in the dark.
 

Donldson

TFP Expert
LifeTime Supporter
In The Industry
Jun 12, 2009
3,418
NW Ohio
You aren't considering the effect CYA has on chlorine. A pool at SLAM will have little negative effect on a cover. The UV from being exposed to sunlight for months will be far more detrimental to the life of the cover.
 

tolian21

Member
Mar 27, 2019
23
NJ
I never have more than 30ppm of CYA.
Yes, UV light is an issue, I am just not sure anything can grow in the dark when pool is closed at colder temperatures. Anyway, I never SLAM my pool before closing and water was always clean at opening. Maybe SLAM is needed it you have mesh cover?
 

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
I never SLAM my pool before closing and water was always clean at opening.
Even at our best attempts each season, some pools simply turn green and others don't. Owners do their best to increase the FC level al bit at closing, while others try the Polyquat 60 route. Still, some pools simply react differently than the year before. It's not an exact science, and pools in various parts of the country react much quicker than others. But owners do their best with the info provided. The cold water certainly helps which is why our moto is always, "Close late - open early". Covers of various types have their own pros & cons as well. If your pool is cleaar each spring, you must be doing something right - don't change it. But for many, the insurance of increased chlorine (or using Poly 60) at closing helps get them through those critical 4-5 months.
 

Pool_Medic

Well-known member
Apr 1, 2018
611
Bangor Maine
I never raise my pool for closing. Make sure waters sparkling clear. Just add poly60 and close end of September. Always open to clear water in late April. I have a safety cover on my pool which allows fine sediment in. Three years ago we had an incredibly mild oct/nov, I was worried but the poly60 did it’s job thankfully.
 
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tolian21

Member
Mar 27, 2019
23
NJ
I never raise my pool for closing. Make sure waters sparkling clear. Just add poly60 and close end of September. Always open to clear water in late April. I have a safety cover on my pool which allows fine sediment in. Three years ago we had an incredibly mild oct/nov, I was worried but the poly60 did it’s job thankfully.
Yeah, I dont think SLAM is always a must at closing. Solid covers are expensive, if I can help it last a bit longer its a win
 

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