Brown Spiky Algae?

[DrMadness]

Hello, so my tank seems to be growing a lot of brown algae on the walls, substrate, and rocks. Some of it even looks like spikes or thorns that are starting to grow and wanted to see if anyone could identify this for me and tell me if it's a problem? Also does my dark green algae look like its dead? Ive received 2 different kinds I believe because one is lighter colored than the other. Parameters seem to be alright.

[DrMadness]

That seems to be a lot of algae growing in there? What was your source of water? How long has this tank been set up?

I used distilled water mixed with fish store salt water. Tank sat for maybe 2-3 months before I added the shrimp. The shrimp have now been in there for a month. It wasn’t this bad when I first put them in.

[Dch48]

I've never seen that brown spiky stuff before. Do the shrimp graze on it?