I bought an Alita AL-6A Linear Air Pump with the 12-gang manifold from Ken’s Fish for $115, along with some airline tubing and three large sponge filters. I’ve been frustrated with my current filtering options on my 90g Oscar tank and my 110g African cichlid tank, so decided to do what a lot of my fish buddies have done and go with sponge filters for biological filtration.
One of the reasons I went with the Alita AL-6A is because of reviews from several CCA members that indicated how quiet they are. I’ve never liked the AquaClear HOB filters, despite their reliability, because they tend to be fairly loud. I cannot believe how quiet this air pump is. It is probably as quiet or quieter than most of my Eheim canister filters.
The big advantage of sponge filters is that you can get a lot of bio load filtering capacity fairly easily and cheaply, they are easy and cheap to clean or replace, and an air pump is fairly energy efficient (the AL-6A only consumes 13 Watts). And it is powerful enough to handle up to 20 outlets, which means I could provide filtration for 10-15 tanks. It will certainly be more than enough to handle my 90g, 110, and the 150g when I get that setup.