I just recieved two Tunze 6025 units and put them in my tank. After doing this I must say that I was kind of hoping there would be a little more flow. It is a 3 foot long tank. Don't get me wrong I think they are wonderful little pumps, but I almost wish I would have went with 1 6025 and 1 6045 for a 3 foot long tank. The tunze are positioned on opposite sides of the tank facing the middle so their streams collide.