| Contrary to common belief, biological filters do not | | | | to spilling into the lower koi pond. |
| process or filter the solid waste of fish in your koi | | | | An adequate ratio of plant cover for the koi |
| pond. They continue to build up and putrefy, | | | | pond's surface is approximately 20 to 30 percent. |
| creating a breeding ground for harmful species of | | | | This is a basic rule of thumb and many factors |
| heterotrophic bacteria which are pathogenic to koi | | | | can change this equation. For example: koi fish |
| fish. As stated, the biological filtration process | | | | population, water temperature, and debris |
| utilizes Nitrosomonas bacteria to break down | | | | accumulating from leaves or over-feeding the koi |
| ammonia into nitrite and nitrobacter, further | | | | fish. I have said many times that the Koi Pond is |
| converting nitrites into nitrates, which is less | | | | the koi's living room, dining room and toilet. |
| harmful to koi fish. | | | | Please invest in the health of your fish. Purchase a |
| Plants now utilize the nitrate and phosphate for | | | | koi pond test kit from any pet or pond store. |
| fertilizer; if you have not provided an adequate | | | | Invest the time to read the directions and start |
| ratio of water plants to koi fish, "hard" algae | | | | regularly testing your koi pond. Remember, clear |
| (growing on rocks and koi pond walls) and "free- | | | | water does not mean clean! As in the water we |
| floating" algae use nitrate and phosphate to | | | | drink, just because the water looks clear, smells |
| reproduce. The key to preventing this condition, | | | | good, and tastes good does not mean it is clean. |
| called "algae bloom," is to provide enough nonsoil | | | | Most of the most toxic, cancer-causing priority |
| bearing plants such as water lettuce and hyacinths | | | | pollutants listed by the E.P.A are colorless, |
| to compete for the nitrate and phosphate. Since | | | | odorless, and tasteless. Do not ever forget the |
| these two plants are tropical and can only survive | | | | simple facts: You have a toilet in a separate room |
| in warm climates, hardier varieties such as Elodea | | | | of your house. Your scaly friend's living room is |
| and Anacharis will perform well in cold climates. | | | | their toilet, and they have to swim in it. Keep it |
| These plants are commonly used in bio-filter | | | | flushed and clean. |
| ponds. | | | | A pound of prevention is worth a pond cure. dh |
| A bio-filter pond is used in conjunction with shallow | | | | If you do not have a bio-filter, that could explain |
| koi ponds with small populations of koi fish. It will | | | | why your koi pond is a tad green, stinky, or |
| also eliminate the need for a mechanical bio-filter | | | | cloudy, and why your finned family is gulping air |
| and a second pump to operate it. The bio-filter | | | | on the surface. Trust me. That will not be for |
| pond is located higher than the main pond for two | | | | long. Fish gulping air to survive would be like you -- |
| reasons. It prevents the koi fish from eating the | | | | in an attempt to avoid breathing poisoned air -- |
| plants and it allows the water from the waterfall | | | | gulping water to survive. |
| to be filtered as it passes through the plants prior | | | | |