Cycling Koi pond

Biofilters rely on nitrifying bacteria to remove toxins produced by Koi from water and then oxidize them as virtually innocuous by-products. Since all bacterias are living organisms, you require two basic things, food and shelter. Their shelter is your biological filter and their food is ammonia that Koi excretes.

Nitrifying bacteria need time to multiply and colonize your filter. This is known as cycling. It usually takes 4-6 weeks for the nitrifying bacteria to accumulate sufficient numbers to track the fish load in the pond. There are two types of nitrifying bacteria, Nitrosomonas, which take care of Ammonia and Nitrobacter, which takes care of nitrite.

Before putting your Koi in your pond, your biological filter is dead. There are no nitrifying bacteria living on the media. This means that if you put Koi in your pond, the toxins are not oxidized and accumulate. If no action is taken, the toxins will harm your Koi.

Now, as the bacteria grow and colonizes your filter, the level of ammonia will continue to increase until there is an adequate amount of Nitrosomonas. When there is enough in the filter, the ammonia level will reach its peak, or peak, and it will begin to fall. It will be slow at first, but will grow as more and more bacteria grow. Soon you will end up with enough Nitrosomonas bacteria needed to absorb the ammonia, so that the number of them in your filter will drop a little after the peak, unless you continue to add more ammonia. The same thing will happen for Nitrite with the bacterium Nitrobacter.

If you did not know, Nitrobacter turns nitrite into nitrate. Nitrate is not toxic at low concentrations, but high levels may be immunosuppressive. Nitrate is controlled by changes in water and / or large amounts of vegetation.

If you did not run a biological filter, your Koi will have to pass through the ammonia and nitrite Spike.

There are two things you can do to prevent this:

Buy a cheap goldfish and put it in your pond to run the filter.

Put ammonia in your pond to run the filter.

The best option is to put ammonia in the pond. The cheap goldfish can be loaded with parasites and it is not good to pass them through the ammonia / nitrite tips.

How to cycle a filter

Add Some ammonia to the water, enough to bring the level to 5 - 8 ppm. Add more or less ammonia depending on the initial fish load. Remember, it is safer to grow more nitrifying bacteria than necessary. Make sure there are no additives in the ammonia that you use that could harm your Koi. Also make sure there are no fish in the pond. Ammonia is a poison to fish.

Be wary of pond products that claim they can speed up the recycling process.

The cycle is the natural way to clean organic toxins. Nitrifying bacteria are slow-growing bacteria and nothing in a pot or box will grow them faster.

Make sure you have a test kit and frequently check the quality of the water.

You will need to be able to test for:

• Ammonia
• Nitrite
• Nitrate

After a while, you will notice that the nitrite levels will increase and ammonia levels will fall. This means that Nitrosomonas grows in your filters. The level of ammonia will continue to drop until it is gone and you will still have a lot of nitrite in your pond. After a while, you will notice that there will be an accumulation of nitrate in the water. It is Nitrobacter that does its job, it turns Nitrite into nitrate. When all the nitrite is gone, the cycle is complete and your biological filter is ready for the expected fish load.

Before adding fish, make a large change of water to remove nitrate. If you are not able to put Koi in your pond right now, add more ammonia to keep the nitrifying bacteria alive.

(Go back to Koi care)