There is black stuff around my spa tile. It's at the water line and formed in the same direction as the water flows. It just showed up one day. I don't think it is algae or mold only because it's not slimy and when I put my finger nail to it it doesn't come off. There's also no black marks anywhere else but around the waterline. Someone said it is grout that is leaching from the tile? But if something is leaching out of the wall then water would be going in behind my tile causing more problems so that doesn't make sense to me...
I have no idea what this black stuff is...
- Thread starter catwong87
- Start date
- Jun 22, 2014
- 47,855
- Pool Size
- 17888
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-45 Plus
Welcome to TFP! 
Might just be a type of scum line from oils and such. Have you tried a Magic Eraser on it?
Might just be a type of scum line from oils and such. Have you tried a Magic Eraser on it?Black algae tends to be hard to remove. Just to make sure, post up your water test results and maybe try doing an OCLT to rule out algae.
