Hi people! I have a 225gal salt, 2 400w MH lights (I think??) I have about 3-4inches sand and 150lb rock so far. I am working on adding rocks and corals. I just got a really great looking piece of rock,but this will be the first piece I've added since I put the whole thing together. I got the rock at the tropical store that I get everything at, and they said it should be ok to add to the tank, it still has some fuzzy on it but has no bad odor, it is only 3.5 lbs, anyone have any bad experience adding a small rock to a large tank if it might not be fully cured??