I use Rena. It's incredibly quiet.

I have a house full of Aquariums for everything from Ciclids to tetras to turtles. In all those tank I have only one air pump, just for looks. Idealy what you want is to have the surface of the water move around enough to airate the water. The filters I have stir the water enough that I don't need air pumps. I find that the pumps are only a hassle from floating air tubes to rattling units. The only kind of tank I would recommened a pump for is a tank that is tall and not very wide like "hex" shaped tanks where there isn't as much surface area.

Some folks set up tanks with undergravel filters... so thus the need for an air pump.

Schago pumps are the best I ever used, but their pricey.

I have a Tetra Deep water and I am using it outside on my Koi pond with a single line split 20 feet each way. They run 2 1/2 deep on a four inch round (2 of them) airstone. Even in the coldest part of winter this year it has performed fantastic. Its been running two years now. I have had aquariums for 40 years and I am very happy with these.

I'm running the same pump to my pond here on Long Island, Tommy. So far, it's kept a hole in the ice the entire winter. It's a keeper.

-PF

I've always been concerned about pumps. They always fall short... no matter what. I used be a firm believer in the old Silent Giant. That was a workhorse. This tetratec has been holding up just fine.

Tetra Tec DW 24-2