As you can see from the above images I'm getting weird dark line on the ridges of my dry rock. It only shows up on ridge lines and elevated parts, like if you dusted it with graphite for finger prints. and idea on what it could be? If it was algae wouldn't it be over all the surface, not just the higher points?
This is from a new tank, I'm doing a fishless cycle with Dr. Tim's and it's been 8 days into the cycle and my water (from a BRS RODI 4 stage) parameters are:
pH 8.2
Ammonia, Beyond the highest color on a red sea test kit so I'm not sure what it is, at least over 2
Nitrite 1
Nitrate 15
Thanks for any help