Black slimy algea

[mikelam]

I am new to SW. 75 gal reef and fish 5 weeks old. All of my levels are good except that I can not get the nitrates down below 15 ppm. I am getting a black slim on the sand. Any advice will be helpful.

 

[Fish_wiz2]

It's bacteria and not algae but if it is black them ask your LFS (local fish store) about it (not petmart or petco they know nothing) because i don't know how to cure it but they should.

 

[McTeague]

Are you sure it is not dark red?

 

[rbtwo4]

Dude if its black u have got urself a major problem. How old is the tank, what kind of h2o do u use ro or ro/di? 1st thing is why is ur nitrates up???