So I was thinking that after I move in a coype of months I would like to start a salt water tank. But in the beginning I am really interested in an invert only tank with live rock. In a smaller tank (5-10 gallons) would a powerhead for water movement and LR be enough for filtration (with water changes of course). Also where can I find a good web resource for info on keep inverts, specifically crabs and what size tanks they need. Thanks.