green on gravel and rocks

[Black Phantom]

Actually Myka I think he said his skimmer is sucking out a lot not vice versa
Which is a good thing.
Myka is right though. That crushed coral will turn into a detrius magnet and totally drive you nuts. I cultivated the world best 250 gallon hair algae display until I changed mine. Went with a medium sand that my Gobies and other sifters like. Dropped my lawn mower in the tank and within a few months and a couple thousand gallons of water changes, all was well.