OK... I have a hanging filter and have just installed an undergravel filter. I am trying to grasp the process in "plain english for dummies". There are no actual filters like there are in the hanging filter for stuff to go through to clean the water. So... how the heck does this thing work? What is the point I guess?

your gravel works as the filter media. you have a pump or 2 that sucks water to the bottom into your gravel. that's the basics.

it works like this. pump 1 pumps pulls water to the bottom of the tank through the gravel through the plastic filter tray then up the pipe and back into the tank.

they never work well with oscars cos oscars dig the gravel and so mess up your media. with the gravel filter you don't move the gravel about like a canister. hope that makes sense?

Sort of... I guess I don't understand if there is no "filter" in the filter... what is it actually doing to clean the water. Guess I'm just numb when it comes to that stuff. I know it works.. just trying to figure out how it works.

what is happening is the gravel itself is acting as a biological filter media providing a place for the beneficial bacteria to grow, which in turn help keep your water quality up.

exactly Win. you will need a good base of gravel (deep). all the poo will get sucked into the gravel where it will get broken down by the bactiria that is growing in your gravel. your gravel is the filter. I take it you have set a pump up on the plastic base you got? the pump should be set to suck the water into the bottom.

Do it in reverse and your gravel stays clean. You take the outlet from a cannister and push the water down the uplift tube.

If you want to have any sort of UGF with oscars you need to put a gravel tidy in to stop your oscars digging down to the UGf plate and stopping it working

OK... call me stupid but how do you reverse it?

connect the tubing in different ways: the suction to the discharge tube and discharge
to the lift tube.

You aren't stupid at all. You are learning something new, you are bound to have questions. I think you seem pretty intelligent.

Codeman_T USMC wrote:

yeah...its true. we are people of different interest doing different things.
asking questions on things we usually do not do doesn't make us dumb... we are just curious and interested...isn't it?

PAUL wrote:


As I said in my email, I think mine is hooked up wrong. I don't have two different tube set ups. Mine just has an air tube connected to the top of each tube. Inside each tube is a smaller tube with a bubbler on the end. They look like two bubbling tubes.

Codeman_T USMC wrote:


Thanks Codeman... I am trained to save your life but damn if I can understand some of this simple fish stuff!