| Contrary to common belief, biological filters do not | | | | located higher than the main pond for two reasons. It |
| process or filter the solid waste of fish in your koi | | | | prevents the koi fish from eating the plants and it |
| pond. They continue to build up and putrefy, creating | | | | allows the water from the waterfall to be filtered as |
| a breeding ground for harmful species of | | | | it passes through the plants prior to spilling into the |
| heterotrophic bacteria which are pathogenic to koi | | | | lower koi pond. |
| fish. As stated, the biological filtration process utilizes | | | | An adequate ratio of plant cover for the koi pond's |
| Nitrosomonas bacteria to break down ammonia into | | | | surface is approximately 20 to 30 percent. This is a |
| nitrite and nitrobacter, further converting nitrites into | | | | basic rule of thumb and many factors can change this |
| nitrates, which is less harmful to koi fish. | | | | equation. For example: koi fish population, water |
| Plants now utilize the nitrate and phosphate for | | | | temperature, and debris accumulating from leaves or |
| fertilizer; if you have not provided an adequate ratio | | | | over-feeding the koi fish. I have said many times that |
| of water plants to koi fish, "hard" algae (growing on | | | | the Koi Pond is the koi's living room, dining room and |
| rocks and koi pond walls) and "free- floating" algae | | | | toilet. |
| use nitrate and phosphate to reproduce. The key to | | | | If you do not have a bio-filter, that could explain why |
| preventing this condition, called "algae bloom," is to | | | | your koi pond is a tad green, stinky, or cloudy, and |
| provide enough nonsoil bearing plants such as water | | | | why your finned family is gulping air on the surface. |
| lettuce and hyacinths to compete for the nitrate and | | | | Trust me. That will not be for long. Fish gulping air to |
| phosphate. Since these two plants are tropical and | | | | survive would be like you -- in an attempt to avoid |
| can only survive in warm climates, hardier varieties | | | | breathing poisoned air -- gulping water to survive. I |
| such as Elodea and Anacharis will perform well in cold | | | | have a do-it-yourself simple instruction sheet with |
| climates. These plants are commonly used in bio-filter | | | | diagrams, for building your own bio-filter using |
| ponds. | | | | $25-$35 worth of parts from any home improvement |
| A bio-filter pond is used in conjunction with shallow | | | | store. Also includes a shopping list of necessary items. |
| koi ponds with small populations of koi fish. It will also | | | | download free (no sign-in) no obligation... |
| eliminate the need for a mechanical bio-filter and a | | | | Happy koi, peace and joy. |
| second pump to operate it. The bio-filter pond is | | | | |