OCLT question

jlt19

Active member
Aug 20, 2019
40
St. Louis, Missouri
I'm slamming with high numbers to make sure any algae is gone before closing up for the winter.

My CYA is super high, 140, but draining weeks prior to closing wasn't optimal so I chose to heighten FC.

I was able to keep it in the 40s all week and started to SLAM yesterday pm. Easily got to 55 around 7pm and was still there at 9:45pm.

Woke up this am around 9am and still at 55. CC has been steadily 1 or less (using 5ml samples because of high FC target).

So the OCLT looks good. CC pretty good. But I'm still cloudy (though no green anymore!). I can see the bottom fine, just not crystal clear.

I have the ability to test many times this weekend to keep it at 55 if necessary. But is it? Since I have a sand filter cloudiness make take some time, right? But does that prolong the SLAM numbers?

I'm fine with either answer, just don't want to waste chlorine/reagents if it's not necessary.
 

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
Normally yes, we would encourage you to continue the SLAM if the water is still cloudy. In your situation, it's a little tricky to diagnosis for two main reasons I see:
1 - Your elevated CYA may/may not be exact, so determining the appropriate FC SLAM level can be tricky. We never like to guess, so I'd hope that the 140 you estimate is fairly close if you performed the diluted CYA test.
2 - In some cases, a SLAM can be complete, but the sand filter simply needs more time to remove all the dead organics. That's where the slight amount of DE in the sand can help. See Deep Cleaning a Sand Filter

With that said, I'd let you examine which situation may/may not apply to you and go from there. If you have any questions or new developments, let us know. We'll see what else we can do to help.
 
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jlt19

Active member
Aug 20, 2019
40
St. Louis, Missouri
Thanks. I did the diluted cya test for a few days and consistently came up with 140. I've since stopped that though.

I'll just go ahead and monitor this weekend and keep it at 55. It's not too much work. I'll see where I'm at Monday am and go from there.

TBH, I don't even see us using the pool any more this season. We're busy, it's not warm enough really and I already pulled the ladder, so a pita. Just didn't want to close too early or with it being a swamp (which it was 2 weeks ago).
 

duraleigh

Admin
Mod Squad
TFP Expert
Platinum Supporter
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In The Industry
Apr 1, 2007
32,752
Sebring, Florida
One of the criteria for finishing the SLAM is crystal clear water. I'll bet on Monday you will have that. It will help you knowing that your water is in the best possible condition when you close. (close when your water get's to 60 degrees or less if you can wait)
 
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