Brown stuff on dead rocks

[wlng3]

I have a 6 weeks old aq with dead rocks and LR with fish and recently I noticed a lot of brown stuff on the rocks, substrate and glass. I presume they are algae and probably due to too much light. I have a 150 litre tank with 0 ammonia and 0 nitrites.

The fish are happy and healthy. What am I suppose to do?

 

[Anemoneman]

I presume they are algae and probably due to too much light.

They are algae - diatoms. Not due to too much light. You can't have too much light. Diatoms are a normal nuisance in a newer tank. Get a cleanup crew. Grow some macroalgae to compete with it. Do a search of the forum for "diatoms". Don't worry.