What is this?

poolmedic244

Well-known member
Aug 17, 2021
75
Long Island, NY
Pool Size
26500
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
Autopilot Total Control PPC3
Ive left the solar blanket on my pool for a few weeks as the weather hasn't been great since we opened the pool early April.

My FC is at 4.5, the water is clear, and the cartridge has been cleaned. Recently, I came out and found this yellowy tan sludge on the cover (bubble side facing the water) with some stuff on the walls. I also noticed a larger area on the top side of the cover.

I power washed the cover before these season.
Any idea what this s**t is?
 

Attachments

  • IMG20250508113129.jpg
    IMG20250508113129.jpg
    821.3 KB · Views: 16
  • IMG-20250508-WA0034.jpg
    IMG-20250508-WA0034.jpg
    846.2 KB · Views: 16