I have a zoomed501 on a 5 gallon Beta tank and have been pleased with the performance so far. Granted I've only had it for about a month. It takes a couple days for it to purge the air but after that it's really quiet. It seemed a little too strong at first but a few days of buildup settled the flow rate to a comfortable level. It does not have an adjustable flow or quick disconnects however. All things considered it's a good balance for price and performance considering the small selection of canister filters this size.