New member
Aug 17, 2019
Lamar mo
I have a 24 foot above ground pool. Two weeks ago we started seeing what appeared to be patches of sand on the floor . If you try to touch it or vacumn it up it turns to dust and creates no cloudiness at all, the pool is otherwise completely clear.
For 4 nights we cleaned the floor and vacuumed on waste and the next day it would be right back.
We then assumed it was mustard algae and slammed it two nights in a row. Some of them now have a grey border but regardless of how great it looks after a vacumn, it comes right back and more the next day.

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Gold Supporter
TFP Guide
Jul 21, 2013
Northern NJ
Pool Size
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
What does FC 5/10 mean?

We have found test strips to be unreliable. You need to get a proper test kit. We recommend the TF-100 Test Kits or the Taylor K-2006C.

I don’t know how you can follow the SLAM Process with CYA 100 and test strips.

If your CYA is 100 your FC should be 11-13 according to FC/CYA Chart

I suggest you read ABCs of Pool Water Chemistry
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