MikeRad89 said:Looks like whoever had the tank added about 3 inches too much fluorite.
It's green hair algae feeding on the ambient light in the room and abundance of detritis under the substrate.
It all has to go.
Take out the fish and plants, clean the tank with warm water and remove all the algae and add a new substrate no more than 1.5 -2 inches deep.
It's a shame that beautiful glossostigma carpet has to go. I might shed a tear or 10 myself...
It almost look like hair algae...what kind of tank is it? And I might change my answer depending on where it it. In the first pic, it looks as if the there are layers of substrate creating a sort of cliff. Maybe a zoomed out picture/ whole tank picture would be better please? So we know what were dealing with and maybe figure out what was supposed to be in there!