I just started a new tank about a week and a half ago and put some rocks that were a little bit live and also 17 pounds of rock that was really live with purple i have a can filter 750 powerhead 45 gallon tank i was looking today and some of the rock looks black is there any suggestions or help on this it would be greatly appreciated thanks i also had that black sponge looking that that is now falling off the little rock on the bottom salinity is at 1.023 just trying to get this tank cycled