Right now I have a Fluval 405 and 2 Emperor 400's runing on a 90 gal. In the tank I have a 8" Florida Gar, 6"Tropical, 10" Duck Knife, 7" Syno. Cat, and will be putting a 10 " Silver Aro this week. This is a TEMPORARY tank and all will go into a 180 or 240 Later this year. My question is is this overkill on filtration and would one 400 and the 405 be ok? SOme of the fish act as is the current is to much and do not come out and swim as they did before I put the 2 400's on. Thanks in advance.