by Tom Burton

If the bottom of the pond has been sloped a bit to the bottom drains, most of the sediment will make its way from the pond to the filtration system without any help from the koi keeper. The returns through the sides of the pond from the filtration system will produce a bit of a current and keep particulate suspended and headed for the bottom drains or skimmer. However, there are routine maintenance tasks that need to be carried out periodically.

• Purging of the settling chamber. Heavy material will settle to the bottom over time (the amount depends upon the fish load and many other factors) and will need to be drained to waste. This is accomplished by turning off the pump, closing the knife valve in the drain line to stop the water from entering from the pond, then opening the chamber purge line knife valve and letting the chamber empty. Then reverse the procedure to get back up and running.
• Cleaning the material used in the mechanical filter. This is where lighter material that didn’t settle in the first chamber is stopped – “filtered” – from the water. There is a variety of materials used to accomplish this but no matter which is chosen, it must be cleaned from time to time. The use of a powerful stream from a garden hose works well and since we’re not asking this material to work as a surface for the “good guy” bacteria to live on, we don’t need to be concerned about the chlorine killing them off.
• Cleaning of the catch-basket in the skimmer. The dust, pollen, leaves, etc. that end up here, need to be gotten rid of as needed so the water flow is unimpeded.
• Cleaning of the media in the biological processing station. The water going to this part of the system should be as clean and free of particulate matter as possible so that the cleaning of it is necessary only rarely. We don’t want to destroy or reduce the numbers of “good guy” bacteria that take up the ammonia and nitrite for us. So, this cleaning can safely be done in pond water or a small portion taken at a time and hosed off, then another portion at a later date, etc., until the job is finished.

(Carolyn says: We have Nite-Out II to recharge filter media after cleaning.)

• Water testing. At a bare minimum, tests for ammonia, nitrite, and KH should be done frequently (weekly for the first several months then maybe less frequently but routinely and among the first things if there appears to be a problem). Ammonia and nitrite readings should always be zero and KH should always be 100 ppm or above.

(Carolyn says: Did you know Microbe-Lift has various sizes of KH Bio-Active Booster to raise the KH?)

• Water changes. Routine changes of 25% per week in the summer and 10% in the winter are recommended. The primary reason is to replenish the mineral content in the water -vital to fish health. Also, it is the first line of defense if there appears to be a problem – even up to 50% when toxins such as chemicals from lawn or tree and shrub treatments are suspected. Just be sure and neutralize the chlorine or chloramine.