I am SOOO excited! going to pick up a used 90 gal on Thurs. Tank,stand, canopy,w/d, skimmer,pump,rocks,2 mo. old aragonite, all for $300!!!! the guy I'm getting it from has had it as a fish only tank and used tap as top off, will that affect the rocks? I have a tub of rocks that has been spinning in SW for like 2 years(in anticipation of a bigger tank, dont laugh too hard!), would it be better to use that? ditch the rocks that come with it?