I don't get it
The three tetratec's I have setup at work are perfectly quiet and that gurgle from the living filter isn't loud at all. The heater works great and they do a VERY good job of filtering mulm.
I personally don't like aquaclears....I had a 500 on my GF's 20 gallon nano reef, and that thing was the biggest pile....it broke its steadying tab for no reason...literally, we went to bed, and in the morning that tab had broke tipping it backwards and spilling water onto the floor, which in turn made me buy a new impeller on a tank that was two weeks old. Then you had to keep the water level so high to keep it from making that trickle noise it wasn't funny. I don't know, to each his own, but I've never really liked aquaclears or fluvals.....
Caleb