New Green Chunky Algae


New member
Jul 4, 2017
Tuscola, TX
Any ideas what this green/black thick chunky algae is? It sticks to the bottom of my above ground vinyl pool and I’ve been working to scrub it loose and get it all out since summer started. It seems to settle into the divots in the bottom of the pool and attach to it.

I dont know my phosphate level, but I have fairly good chlorine levels and CYA. I had a bad mustard algae problem last year due to off the chart CYA, so end of last year I switched to liquid chlorine. I had almost no CYA at the beginning of the season, I’ve been slowly adding stabilizer to get it up to 45.

Pool is 27 ft x 4 ft round above ground vinyl with pump and sand separator plumbed to two different return jets.

FC 8
CYA 45
pH 7.5
water is super clear.



Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
Jun 22, 2014
Texas, San Antonio/Marion, South-Central Area
Pool Size
Salt Water Generator
SWG Type
CircuPool RJ-45 Plus
Welcome to the forum Ron! :wave: Those deposits do seem a bit unusual - unusual to me anyways. Your signature doesn't specify, but can you tell us what test kit you used for those numbers? In any case, I would recommend doing an Overnight Chlorine Loss Test to see if you have any unusual chlorine consumption happening. Since you had some issues with algae previously before becoming a member, you may not have been familiar with our SLAM Process process for removing algae. If you fail the Overnight Chlorine Loss Test, it would your next course of action.
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