thanks for all the replies, we are planning on getting more live rock but maybe one piece at a time with some cool stuff on it and i was using the filter as a home for bacteria before we got the live rock. So should i take the media out of the filter and fill it up with something else and just use it as a pump? or just get rid of it all together? One other thing, when i got the tank is has a crushed coral substrate, ive heard that could also be a nitrate trap, how would i go about changing over to sand? remove the course stuff or mix it up or add it on top maybe?