Pond Filter FAQ

What does filtration do for a pond?

Depending on your pond’ size a good filtration system will:

  • Biologically reduce ammonia to safe levels for fish.
  • Mechanically remove debris and other particulate matter from the water. 
  • Naturally control the nutrient levels through the plants filtration to maintain clear water and maintain clear water.
  • (Optional): Utilize ultraviolet sterilization in the absence of plants filtration to kill algae and maintain clear water.

Do I need a filter in my pond?

It is not absolutely essential to use a filter in your pond as the plants themselves will clear your water IF the pond is planted properly. A UV sterilizer and/or filter could help clear your water quite a bit faster in the spring while your plants are establishing themselves, and it may help keep the water clearer for those pond owners who have introduced Koi to their ponds and cannot use plants to balance their water.

But in most ponds having a bio-filter in addition to the proper number of plants, is only an asset.

What kinds of filtration are there?

  1. Mechanical filtration traps particles in a material of some type for later removal during cleaning. Clears the water by removing small particles of algae and organic debris.;
  2. Biological filtration- these use beneficial bacteria to feed on impurities in the water; the bacteria break down fish wastes and other organic matter. Clears the water by removing ammonia and nitrite caused by fish waste. Beneficial bacteria live in the filter and convert ammonia to harmless nitrate.
  3. Ultraviolet Clarification treats water with ultraviolet light, minute particles clump together for easier removal by a mechanical filter. Most filters for mid-size and large ponds employ a combination of mechanical filtration and biological filtration. And they can accommodate an ultraviolet clarifier as an option.

How often and with what do I clean my Filter?

The frequency of filter cleaning differs from one filter to another; it’s best to consult your filter manual for suggested timing. Generally, the warmer seasons will require more frequent cleaning but cleaning too often (ex: weekly) can remove beneficial bacteria from the filter and that you don’t want to do. Avoid using chlorinated water to clean the filter, instead use pond water, rainwater or well water.