I just noticed last night a couple of my rocks have that on them now. My tank has been running for about a month.
I add purple up and some other stuff for live rock, i think it's called total spectrum?????
I don't know what it is and i haven't tried scrubbing it.
All my parameters are fine, water's clear, fish are eating. So i'm not really worried.
Oh, by the way i use Oceanic salt. Is that good salt?
What is the BEST salt to use????????