Use clarifier in addition to DE in sand filter following a SLAM?

C3Cl3N3O3

0
Bronze Supporter
May 25, 2015
460
Fort Mill, SC
Pool Size
20000
Surface
Vinyl
Chlorine
Liquid Chlorine
Hello all!

I'm recovering from a swampy pool after removing the cover and have been SLAM-ing for two weeks. This was a rough one. I do get mustard from time to time and maintained mustard algae shock level for the first week or so for good measure (25 ppm FC). For the second week I've been maintaining 15 ppm FC. The water looks reasonably good, however there is some stubborn lingering cloudiness. My overnight FC loss was zero last night, however the sand filter is still working hard as I have to backwash every other day or so. I added a cup of DE to speed things up a bit. My pressure has already increased by 3 PSI. The question is, should I add a bit of clarifier as well?

FC: 15
CYA: 40
Alkalinity: 70

Thanks!
 
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Resist using clarifier. Continue with the DE and see if it clears.

If you insist on using clarifier, get SeaKlear Chitosan. And plan on deep cleaning the sand filter after its use.
 
Thanks for the reply. Is there a specific concern with using clarifier in this situation?
Clarifier is glue. It can gum up the sand if not cleaned out very thoroughly shortly after being used. Thus the deep cleaning. And do not use the cheap pool store stuff.
 
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Yesterday and today saw smaller improvements. A second backwash was required which took longer than the first. I'm getting close to needing a third, and that has taken longer still. So, the sand filter with DE appears to still be working harder than usual but is tapering off. The water looks pretty clear during the day now, however the night light test reveals the persistent cloudiness.

I measured my CH and it is 40. pH is 7.2. I wonder what the fine particulate matter is? Chlorine demand remains normal, approx 2 - 3 ppm / day in full sun. A bunch of leaves got in the pool over the winter and festered in there.
 
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Pool lights will always show stuff. Here’s my pool a couple of weeks ago at night:

4FB08201-AE47-4BE2-9071-41B8953777A1.jpeg

And at the same time, in the light:

392892E8-DBD1-42F8-A1DE-207D4519B91F.jpeg
 
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Clarifier is glue. It can gum up the sand if not cleaned out very thoroughly shortly after being used.

@JohnT said ....

Pool clarifiers rely on the charge difference in the molecules of the clarifier and the particles floating in the water. They are electrically bound together. Once dissolved in water, there is nothing sticky or gummy to clog a filter.


And @mknauss said ....

Occassional use, as JohnT stated, is fine. But do not lull yourself into the though of using it weekly or whatever. Repeated cloudy water is most likely from a chemistry imbalance and the likeliest isssue is algae. So just be aware of that. Repeated use, many pool stores recommend it weekly, will eventually cause a problem in your filter media. But using at the start of the season after making sure you are completely clear of any algae and, if necessary, a full and complete SLAM Process has been followed, will not bring immediate harm to the filter media.

The Internet and TFP never forget. ;)

 
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Pool lights will always show stuff.

Yes, they are very revealing. I look at the water right in front of the light but also look at other features in the pool and make an overall qualitative assessment. It's around an 8/10 right now and has been a 10/10 in the past. We're getting there, slowly but surely.
 
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