I have been running a emperor 400 and a powerhead on my 65 gallon since I bought the tank a few months ago. I was told by all my fish buddies that I should upgrade to a fluval,so I just purchased a Fluval 305 yesterday and hooked it up.I watched the installation DVD and read the book carefully so I wouldn't make a mistake in the install. When I awoke today 2 of my fish had died and the rest looked bad,they were all at the top of the tank gasping for air. I didn't know what the problem was but I assumed it meant they didn't have proper oxygen. I put my powerhead back in and turned it on within 2 hours the fish looked better and no others died. I called the Fluval Customer service to ask what went wrong and i was told to remove the powerhead and not use it again with the fluval,but when I do the fish start acting funny again. I was told by CS that the Fluval should provide plenty of oxygen for the fish and to move the exaust to right at or just above the water level to create a better current,so I did. Now it is so loud I can even hear my TV and there is no change with my fish.I thought the whole idea of the fluval was to reduce the water noise ? So now i don't know what to do,I don't want to lose my whole cichlid tank just because of this filter. Please help !!!!