Anyone else out there have these. I have 2 in a 90 fallon Fish only tank. Thought I was getting the best! My problem is the magnet concept. It's make my tank very noisy! The magnets seem not strong enough to really keep the heavy motor out side of the tank in place. If it's not alligned perfect, there is a vibration! I have even tried to remove the spacers/ duct tape it to the back of the tank....I even considering getting rid of them and replacing with a Tunze or something...But they are expensive and How do I know I won't experience the same problem. Can anyone speak from experience...These things move serious water!!! I really like the movement!!! Any advice would be appreciated!!