I agree with ryshark completely on the crushed coral. Overall, it is not a good option for reef tanks or inverts, because crushed coral can cause an excess of nitrates, and too high of nitrates are bad for both. Only thing though, is if you have CC, you want to thoroughly clean it, all the way to the bottom of the crushed coral layers, or you wont get all of the nasty stuff that lays undetected under the crushed coral.. rotting away. And that is the stuff that causes the excess of nitrates. I would say clean it a little more frequently then once very month though. And if possible, change over to sand whenever, or if you ever get the chance to. It will make all the difference in your tank. You won't even need to clean the sand either because your clean up crew will find it easier to eat the detritus that builds up on the top layer of sand, rather then all the way at the bottom layer of crushed coral, where they can barely get to. Sandbeds ftw.