fluidized Bed filters...what is it?

[tropicfishman]

I hear alot of tank about fluidized bed filters and see them in my fish catalogs and stuff, there not really that expensive, and apperently you fill them with sand or something, anyways what are they used for? what do they connect to, a pump, a canister filter or something? thanks for any help

 

[toddnbecka]

They are used for biological filtration; a load of sand has plenty of surface area. They are usually powered by a water pump of some sort, what kind depends on the particular filter.

 

[Andos99]

Water is pumped up through the unit, lifting the sand into a "Fluidized bed" (hence the name). The beneficial bacteria attached to the media (sand) utilize dissolved wastes (ammonia and nitrite), oxygen supplied by the customary water fall device and other required nutrients from the passing water converting them to relatively harmless nitrate. The sand grains are in continual free fall through the water resulting in an excellent transfer capability between the water and the bacterial film on the media. The enormously high surface area combined with this excellent transfer capability creates the perfect habitat for bacterial growth. In addition, the sand grains bump into each other frequently knocking off excess debris and providing a self cleaning function which allows new areas for bacterial growth.

 

[tropicfishman]

pretty cool

 

[BillD]

The only negative I have heard about is that over time the grains will get smaller as they bump against each other, and small bits break off. These dust size bits end up in the tank. For the size of them, they provide a phenomenal amount of surface area, and are virtually maintenance free.