Filtration Types

Mechanical vs. Biological Filters

There are two basic types of filtration - mechanical and biological.

The purpose of a mechanical filter is to screen dirt, solid waste and algae out before it gets to the pump. This type of filter can be high maintenance as it requires cleaning several times a week, and sometimes everyday, depending upon how dirty the pond it. Usually, the pump sits inside a filter box.  As the pump sucks water, the water is pulled through a series of filters. Debris and other matter is caught in the filter mats. As the filter mats get clogged, the whole filter box needs to be removed from the water and cleaned. Usually, a garden hose will work for cleaning, whoever it is important to not rinse the filter mats into the pond.

The purpose of a biological filter is quite different. Waste products (dead organic matter, uneaten fish food, fish excreta, and the fish-harming ammonia gas are all turned into harmless materials by the bacteria and tiny organisms which flourish on the filter medium.

The filter must be run continuously as the bacteria will die in a few hours if the pump is switched off. The full effect of a biological filter will not be seen for several weeks after switching it on.

Most ponds 500 gallons or less usually have a pump which is placed inside a plastic (strainer) container. This is a mechanical filter and only serves to filter out large sediment. If you have a pond that isn't equipped with an external or internal biological filter you must use algaecides to keep your water clear. Some ponders just deal with the cloudy or green-pea soup water.

With ponds larger than 1500 gallons it is now both feasible and practical to utilize a skimmer box (like a swimming pool skimmer) and a biological water falls box. These both work very well together as the skimmer box collects the larger debris (leaves), and the biological waterfall box hold media to create the biological filter. This is also an easy way to create a beautiful water fall without much effort. For more information about his system, please contact us.

first mechanical filter
Second Mechanical Filter
First Biological Filter
Second Biological Filter