My hubby and I had a 75g reef tank before. And I remember starting it like this as follows: Mix salt and water in tank and circulate,then add the sand,and then the cured live rock and cycle. However we no longer have the tank and have bought a 55g to start over. But some things are different this time. We bought about 20lbs of Atlant. rock locally,with bright sponges,well alot of stuff on it. I asked the keeper if it was cured and he looked like he had no idea about what I was asking. He said it should be put into a running aquruiam. I have no idea if this rock is cured or not. It has tremendous growth of stuff. Next, we have ordered Caribbian live rock 40lbs comming in about 24 hrs. Uncured. So here are my ques. I will be curing these rocks in my tank. Can I put the Carib. with the Atlan. at the same time to cure? And do I add the subtrate after curing the rock or before? It seems that it would be easier to clean out the dead stuff with out the sand. This seemed alot less confusing before. I bought the rocks cured then cycled! I just do not want to kill this rock I am not sure what is on the Carib. yet but the Atlantic is so alive with growth from corline,algae,sponges but is it supposed to if it has been cured? Please adivse I only have a day to figure this out! Thank you 8O