First SLAM... Question about pH levels and water temps

roamin

Bronze Supporter
May 4, 2020
31
North Florida
Pool Size
4500
Surface
Vinyl
Chlorine
Liquid Chlorine
Two main questions relating to the SLAM process:
  1. How important is the 7.2-7.5 pH level during a SLAM?
  2. Does water temperature affect the SLAM process? (Water temp just hit 60F last night/today)
I started my first ever SLAM today. During the swimming season I kept the pool at 6.5-7.0 FC and 7.6 pH and never had any problems. Water has been too cold for swimming for about 5 weeks now, and I've just been maintaining the FC level. Without us in the pool every day and with the chlorine usage dropping due to lower temps and less sun, it's allowed me to get quite lax about checking the levels so I've had some big swings getting down to 2.0-2.5 a few times. The pool is also under two large trees so LOTS of leaves are dropping. I still only have the solar cover on the pool and thought it was catching most of them on top. I noticed about a week and half ago that the water was starting to turn green, but just barely. It's been 3 days since I checked the water and decided today that I'd go ahead and get all of the leaves off the cover and when I got out to the pool realized it was much greener and quite hazy. After getting all of the leaves off the cover, I realized just how many leaves had actually made it into the pool over the past few weeks ( TONS :cry: ). I tested the water and FC was 0. Oops.

I spent 30-45 minutes with the net, going after all of the piles of leaves I could see. It was getting dark and and the more I scooped out leaves, the more I stirred things up and the murkier the water got. I know there's still a lot of leaves and debris in there, so I have more scooping (and eventually vacuuming) ahead of me tomorrow. Before heading inside I made sure the skimmer and intake were clean and upped the FC to 12 (based on Pool Math App recommendation for my CYA level which I verified was at 30 before I started). I checked the FC level about 3 hours later after the kids went to bed and it hadn't dropped any. Will check again and adjust in the morning before work, and then spend the evening tomorrow cleaning out as much debris as I can before dark.

My only real questions at this point are about pH and how the colder water (60F) may affect the SLAM process. I just looked up the SLAM procedures to get a refresher since I read them several times before we set the pool up over the summer, but I've never had to use them. They said to test and adjust pH to 7.2-7.5 BEFORE starting the SLAM. During the season, my pH stayed pretty consistent between 7.5-7.8 so I got used to only checking it every 3-4 days and aerating for a day or so when needed to bring it back up a bit. Since we quit swimming, I hadn't really been checking it consistently at all. Last check was about 2 weeks ago and it was 7.6. I assume it's probably higher than that now, but I don't really know. I'm just curious how a lower or higher pH might affect my SLAMming efforts? The SLAM instructions say that the pH test isn't reliable during a SLAM, so I assume I'm stuck with whatever it is (and not knowing).

Anyway, all guidance and thoughts are welcome and appreciated. Didn't mean for the post to be so long, just documenting everything so I can refer back to my post history in the future if I ever need to.

(Also, maybe this is weird, but I'm actually kind of glad this happened. I'm happy to get the experience dealing with a SLAM and getting the water back to clear when it's not swimming season and my kids are mad at me that they can't swim! :ROFLMAO:)
 
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The lower pH is pretty important. One, it helps make the chlorine more effective at killing algae, second it normally can not be checked during the SLAM Process as the FC is above 10ppm. Test your pH when the FC is 10 ppm or less and adjust the pH to 7.2

The lower water temperature slows down everything. It slows down the growth of algae and it slows down the impact of chlorine on the algae and the consumption of FC. So be patient.
 
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Have been letting FC drop, finally got down to 7 today. Tested pH (7.6-7.7) and adjusted to 7.2. Brought FC back up to 15 to restart SLAM and brushed the whole pool. Also hooked up the small Intex cartridge filter that came with the pool kit for extra filtration during the SLAM. It's on now! :cool:
 
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