Nothing growing on live rock!

[Reef_rookies]

I have a new 55 gallon tank that's been set up for about 2 months. There is about 47 pounds of live rock in tank and all of it has grown coraline algae except one rock?

 

[boojumsnark25]

I wouldn't think there would be any reason that the rock "can't" grow coraline, more likely that it just hasn't spread to that rock for some reason. Is there another rock w/ coraline that is touching that rock to help it spread? I've heard that scraping some coraline with a razor blade sends a bunch of spores into the water...that might help some of them settle onto that rock

 

[Reef_rookies]

I wouldn't think there would be any reason that the rock "can't" grow coraline, more likely that it just hasn't spread to that rock for some reason. Is there another rock w/ coraline that is touching that rock to help it spread? I've heard that scraping some coraline with a razor blade sends a bunch of spores into the water...that might help some of them settle onto that rock

Thanks....I took the rock back and exchanged it for another. Just thought it was very strange as every other rock has coraline covering them!