Black spots on dry rock

[kwandrsn]

I bought some dry rock and I noticed some of it has black spot that wont scrub off. Is it safe to still use. I bought about 80lbs of it and probably half of it is like this.

 

[Mike J.]

IMO it's probably decaying organic matter of some sort; it's also unsightly. If I was in your shoes I would soak the rock in a bleach bath for a day or two; 1 cup bleach per gallon. Then rinse it off and let it dry in the sun. Same thing you would do with a sand dollar to turn it white and stop the decaying process.

 

[kwandrsn]

Bleach and saltwater scares me but I may try it if anybody else thinks it is a good idea

 

[Mike J.]

I do the same thing with my filter socks, pumps, and equipment on a regular basis.

 

[bairdimusprime]

the bleach works! and so does a power washer

 

[kwandrsn]

Well looks like ill give it a try