How Do Gravel Water Filters Work?
- Gravel filters, also known as "undergravel" filters, work by drawing the fish tank water through gravel, which traps microbes and bacteria. Because they have a tendency to get clogged, which can cause harm to your fish, there is a bit of controversy over the issue of whether or not gravel filters should be used. Proper maintenance and attention to the tank condition can ensure that this simple filtering method continues to function correctly and will pose no danger to fish.
The gravel filter system consists of a filter plate that lies beneath a layer of gravel. The tank water flows freely under the gravel. - Air pumps or power heads push water through the gravel, which becomes a biological filter. The air pump blows bubbles up into a lift tube, which pushes the filtered water into the tank. The power head is a mechanical pump which pushes water out of the top of the lift tube into the tank. Water that gets pushed out of the lift tube is replaced by water from under the filter plate, which pulls water through the gravel to clean it. Because all of the water is coming from the tank system, it has the same temperature. This means there are no cold or warm spots in the tank water, which is good for the fish and also inhibits the growth of bacteria.
- Although you do not need to clean the tubes and filter plate on a regular basis, you will need to be sure to keep the gravel clean for proper operation of the system. You can purchase a gravel vacuum at your local pet store, and clean roughly 1/3 of the gravel each time you change the water in your tank. (You should change your tank water weekly.) Vacuuming your gravel regularly will keep bacteria from clogging up the filter works, which would cause a reduction in your tank's water flow.