Though there are more powerful filtration systems
available for aquariums, there is no denying that the undergravel filter is effective in its own right. It is a very simple filter -- biological, to be exact. It is placed on a shaped plate made of plastic. Then, the plate is put on the bottom of the aquarium. The plate has slots through which water passes through to get into the gullies. It also has a riser tube connected to it to draw up the water to the surface. A powerhead enables the water to move up.
Simply put, the undergravel filter is just a plate with gravel on it. Yet, it is very effective because it pulls the water in to go through the gravel, then the good bacteria growing on the surface of the gravel dissolves the soluble waste found in the water. Thus, only filtered water gets to go back to the surface. Simple, indeed, yet reliable.
If you want to put in an undergravel filter in your tank, use Lee's Aquarium 1 Gal Undergravel Filter from Pet Store
. It is a very small filter, perfect to use for small one gallon fish bowls wherein the usage of complicated filtration systems is unnecessary. In spite of its size, Lee's Aquarium 1 Gal Undergravel Filter is already a complete system in itself, with a four-inch plastic plate and a riser tube that can suck in water to draw up to the surface.
Lees Undergravel Filter for Fish 2 Gallon Filsh Bowls allows you to maintain fish safely in a bowl or small designer aquarium for extended periods of time. Minimizes maintenance responsibility. 1 gal. has 4 inch diameter / 2 gal has 5.25 inch diameter