Discoloration on rocks

[horn1893]

So my 55G tank has been running dor about 6 or 7 months. Have four fish, 1 blue leg crab and one tiger conch snails. Everyone seems happy and get along.

My question is the color of the back of my rocks. I think it's some kind of algae but it is only on the back side of my rocks. I can see green areas but some areas are dark red possibly black. Mostly on the top and back of my rock. Is this mold...or algae...good or bad?

 

[Mr. Mojo Rising]

it looks like the beginning or regular green algae. The red might be the beginning of cyanbacteria. Both are somewhat normal in new tanks. Do you have any flow in your tank.

 

[horn1893]

it looks like the beginning or regular green algae. The red might be the beginning of cyanbacteria. Both are somewhat normal in new tanks. Do you have any flow in your tank.

Thanks and that is what I was thinking as well but wasn't quite sure. Just weird it's mostly on the back side of my rocks. I do have flow but it's towards the top of the tank. If I turn on the other power head it creates a sand storm. I have to find a slower or less powerful fan.... thinking of changing the substrate as well lol

 

[Mr. Mojo Rising]

Thanks and that is what I was thinking as well but wasn't quite sure. Just weird it's mostly on the back side of my rocks.

Any chance the tank is near a window? That could be it if so.