under gravel filters

[tramca]

We have a UGF and it baffles me exactly how they work.
Yes it's connected to the pump, and yes it blows bubbles up the tube etc.
It looks quite nice actually. But I wondered how it breaks down the waste from the fish?
Does this filter mean no more cleaning of the gravel?
Or does it mean less waste left in the gravel?

Also how important is it to use real plants as opposed to plastic or silk plants?

 

[catfishmike]

an under gravel filter works like this=water and air can't occupy the same space so as the air pump forces air into the uplift tube water is displaced by air the moves to the top of the uplife tube.the air forces all the water above the pump exahust to move out the top of the uplift tube.now gravity doesn't let water remain at an unnatural level so now the space occupied by the air is filled with water that rushes in to catch up with gravity,drawing in tank water through the plates of the ugf to replace the water displaced in the uplift tube.the gravel act as the breeding ground for benifical bacteria.so as the water is moved through the uplift tubes it must first pass through the gravel and ugf plates.the gravel at the bottom of your tank acts as both mecanical and biological filters.unfortunately this means that you will need to vacume as often as normal if not more often as this is your mecanical filter.you may wish to fit your ugf with a reverse flow powerhead.this will push water down through the uplift tube and up through the gravel.for this to be truly effective you must then fit your tank with a hob filter to catch the detrius in the water.lats real plants take up some waste byprouducts as nutreints.but you can get by with plastic if you have a brown thumb