Nasty hair algae! I had a few strands in my 35L, they grew very quickly but then disappeared very quickly.
I found that when I pointed my spray bar downwards the flow wasn't reaching the other end of the tank so beware of that. Different shape & sized tank so it may work for you.
I found that when I pointed my spray bar downwards the flow wasn't reaching the other end of the tank so beware of that. Different shape & sized tank so it may work for you.