Biological vs Mechanical Filtration

Filters are used to remove suspended particles from the water (mechanical) or they are employed to process the water biologically, removing nutrients and organic pollutants using bacteria. A mechanical filter is attached to the intake of a pump and is submerged in the pond. The filtration media is fine-pore polyester that traps the particle until it is removed by you and rinsed away using a garden hose. The biological filter uses the same material but is located outside of the pond on the outlet side of the pump. The water flows through the material, which harbours a colony of beneficial bacteria which cleans the water. Ideally a biological filter would be pre-filtered with a mechancial filter to keep the media as clean as possible to maintain peak efficiency.

To figure out how much water is in your water garden, measure the pond length, width and depth in feet. Multiply the three numbers to obtain the cubic volume of the water. Multiply this number by 7.5 to get the total number of gallons of water. If the surface of the pond is irregular, try to estimate the actual square footage as close as possible before multiplying with the depth. The depth should be an average depth, not the deepest point. Average length X Average width X Average depth X 7.5 = gallons of water. An alternative to measuring pond volume is to use a water gauge for the garden hose that can be purchased at a hardware store. Another possiblilty is to record the amount of time it takes to fill a five gallon bucket, then time the filling of the entire pond and divide the total number of minutes by the time it took to fill the bucket.

Filtration Tips

A floating filter means it needs to be cleaned.

It takes time for a bacterial colony to develop; wait four weeks before adding fish to a new pond.

When cleaning the filter media, rinse only enough to remove the silt and dirt. You don't want to rinse so thoroughly that you was away bacteria.