dirt or algae?

[ElitePirate]

Hi

please see my attached pic. is that just dirt or algae? it's brown sand kinda dirt. I don't think algae. I have a cleaning crew but it's like this for a while now.

Any idea what is this? i know i can just use a scraper and get rid of it but i'd like to know what is this and how can i clean this naturally.

 

[Paul B]

Algae. And it is normal.

 

[ElitePirate]

hm i have 3 cleaning snails but i dont see them cleaning the glass that much.

if i have 3 snails, 1 blue legged hermit crab and a yellow gobi as my cleaning crew, is it too much to add some more cleaning crew members? I cant add any more fishes because my tank is too small.