I purchased a rock with a fine grass algae on it. I was told it was macro algae and would assist in the development of copepods. The algae is green and very fine like hair. It grows in clumps on the rock. Anyways, my tank water now stinks. Is this normal or is this an indication of something wrong? I tested the water and everything checks out normal (zero nitrate, nitrite, ammonia). The algae rock was placed in my 24g nano cube.