How To Choose The Right Biological Filter?

Finding the correct filter system for your koi pond can be complicated, having so many types and variations of filter on the market – where should you begin?

What filter size should i choose?

You have to make sure it is correctly sized, can deal with the flow from your pump and will get rid of all the waste generated by your koi. It has to be easy to clean and have plenty of surface area to transfer all the ammonia out of the koi pond.

Pond fish develop waste in the form of ammonia, which is discharged into the water through the gills. Ammonia can also come from the dead and decaying plants in the pond or from untouched food. Ammonia is a chemical and it is toxic to koi and other pond fish.pre-filter6

In a complete pond with a working filtration system the ammonia is broken down by Nitrosomonas species of bacteria to a secondary product, known as nitrite.

So how do you choose the (pressurized) filter size? It’s always a good idea to “oversize” the filter by simply cutting the gallons in half. So, if your pond is around 1500 gallons, use a filter that’s meant for 3000 gallon pond, that’s it. If you have a mechanical filter also, then you can get a smaller filter since the mechanical filter already receives clean water.

Most ponds should have the water going through the mechanical filter before it gets to the biological filter.

And, keep in mind, the more fish you have, the more important biological filtration is to keep the ammonia levels in your pond inside the safe levels for your fish.

Can Nitrifying Bacteria Help?

If you don’t want to invest too much, you may also look into adding an Microbe-Lift microbe-cleaner-pond1Nite-Out II to your pond to support the growth of a colony of nitrifying bacteria. Microbial consortium of nitrifying cultures can speed up the nitrogen cycle in your pond which will result in cleaner, better water and a healthier environment in the pond for your fish.

It establishes, promotes or stabilizes and maintains nitrification in pond waters and eliminates the toxic effect of ammonia.

The only disadvantage to this is you need lots of it, need to pour it to the pond quite often, and even then it will not be as effective as a bio filter.

Final tip: The best way to keep your pond absolutely healthy, would be to use both types of filters – biological and mechanical and every now and then add the nitrifying bacteria. The filters must be cleaned every month also.