Rock Cleaning

[Sailfin]

I recently bought a cichlid tank.....and the white coral-like rocks were coated with green-black spots........is there a way to make these rocks white again?

[HappyGuppy]

Two methods that I've done with rocks & decos, also with similar algae, is I've boiled them, or I let the sit in a bleach bath over night.  The bleach worked well with my white gravel.  Made them extra white.  Of course both methods kill any good bacteria on them,  but it is not that big a deal if you have an otherwise mature tank.

If you chlorine bleach the rocks be sure to rinse rinse rinse rinse rinse rinse rinse rinse rinse rinse rinse rinse rinse rinse and even if you let it air dry for a couple days that would be even better.

[HappyGuppy]

Oh wait.  Just reread your post and noticed that you said *CORAL ROCK*.  In that case I'm not sure the best options, and thus defer to someone more marine experienced.