Hi all I have a 100gal tank thats well established with oscars and chilids and I just got a new tank from my uncle with is 200 gal. I was planning to do a quick change from drainning the tank taking out the fish and then moving the old tank and placeing the new tank in its place and using the old filtration with new water. Would their be any down fall with my fish doing this if so, what is the best way of doing this?