You should have live rock in your frag tank or in the sump connect to the frag tank. What I did was hook my frag tank into my main system that way I could put everything in that day. I didn't have to buy live sand or LR just new lights. I had sand in the bottom and got rid of it, it just collects junk and is more of problem. I would rather have a sump/fuge in line than live sand if thats possible.