AG closing slam question

[Dcookster]

I’ve been running my swg 24/7 to get chlorine levels up. It’s at 16.5 so just checking. So it’s time to shut off swag now right? My CYA is at 70, so I need to add enough bleach to bring that 16.5 to Slam level of 28? Also before throwing cover on, is it recommended to use that polyquat algaecide? Water is 55 degrees now and I’m hoping to get it closed up this weekend. Thanks for any advice

 

[Texas Splash]

I suppose our first concern should be are you increasing to SLAM level just to help get you through the winter, or do you actually have algae? If it's a true SLAM for algae, of course you'll want to pass all 3 criteria. But if you're just increasing the FC as a final boost before closing, I'd turn off the SWG and just hit it with regular bleach then cover it. You don't want to add Poly when the FC is really high anyways because the chlorine will just oxidize the Poly (waste). Your water is cold enough to where organic movement should be extremely slow.

 

[Dcookster]

My pool is crystal clean, I was under the assumption that slamming it was needed before closing? I was reading Closing (Winterising) Your Above Ground Pool, it says Bring pool water to "shock" level? Is shock level and slamming to different things? Chlorine / CYA Chart says Shock FC 28?

 

[Dcookster]

I just discovered my Pool Math Chart says, Suggested FC Levels - in the box that says SHOCK it has [16], so I guess I’m good like you said?

 

[Texas Splash]

You have the concept correct, and also that the closing instructions recommend increasing to SLAM level. Due to owner timing however, some try to close before the FC has a chance to fall a bit. If the FC is at SLAM level it can oxidize much of the Polyquat 60. So it's a personal call. Based on your CYA, you can increase the FC about halfway to SLAM level then add Poly, or just increase to SLAM level and not use Poly.