Undergravel Filters

[Liquidskate750]

Just want to know how these work. I just bought a Top Fin undergravel filter and put it together and figured out theres not power cord to some kind of motor like thing that sucks up the water and spits it out somewhere. So can anyone explain to me how they work? Do I need to buy some other thing to make it work or does it work by just sitting there? Thanks!

Sorry if this has been posted somewhere else already.

[Gambusia]

You use them with powerheads.

[Raskolnikov]

I found RTR's article:
http://www.aquasource.org/CMS/modules.php?op=modload&name=Sections&file=index&req=viewarticle&artid=17
to be a fantastic introduction to undergravel filtration. I'm currently using a RFUG in a 16g tank with a penguin 660r powerhead.

[sky.eyes.woman]

How big a tank is this for? If it's something under say...20 gallons an air pump with diffusers or air stones attached to rigid tubing inside the uplift tubes will work fine and not create too much current. If the plate is for a small enough tank that it is in one piece you won't have to have 2 uplift tubes on it if you don't want them both. I noticed the Top Fin UG filter for a 55 gallon is in four (!) seperate pieces with no way to interconnect them so you'd have to have four powerheads on it for full coverage.

I'm still debating whether to use mine or not, it's a Penn Plax that is in 2 pieces and I only want to use one powerhead. I thought about cutting one end off each plate to overlap them but that won't work for the Top Fin one if you have a 55 gallon or lager.