Nitrites and Nitrates are natural by-products of waste. Leftover food and the waste products from fish create ammonia, which bacteria then convert into nitrite and finally nitrate. Both of these can be toxic to fish if they are not kept below safe levels.
What Are Safe Levels Of Nitrite And Nitrate?
In a koi pond, the ideal level of nitrite is 0.00ppm (parts per million). A level of 0.25ppm can prove fatal to fish. The ideal koi pond nitrate level is anything from 20-60ppm. At around 80ppm, you should be looking to make changes to reduce the levels. Anything above 120ppm of nitrate is extremely toxic. A koi water test can accurately tell you the levels of nitrites and nitrates in your pond.
Indications Of High Nitrite And Nitrate
If you notice your koi are acting dull or lethargic, then you may have an issue with high nitrites or nitrates. High nitrate levels are harmful to fish, causing a condition known as brown-blood disease. It can also damage veins in addition to the immune and reproductive systems. Lethargic fish can pick up briefly after feeding if you have a problem with nitrates.
If your fish are gasping at the surface or spending a lot of time around airstones, you may have high nitrites.
How To Test Koi Pond Water
It is important to perform a koi pond water quality test regularly. This allows you to promptly identify high nitrite or nitrate and take actions to reduce them.
It can be difficult finding the best water test kit for koi pond water. Hanna Instruments make water testing easy, and we offer one of the best pond water test kits that return fast, accurate results.
How To Reduce Nitrites And Nitrates
Reducing excess nutrients in a koi pond uses the same methods as, for example, reducing nitrate levels in a fish tank. Changing between 1/3 and 1/2 of the total water volume of the pond will help rapidly reduce nitrite and nitrate levels. If you have extremely high levels, you may need to do this daily until you get to non-toxic levels. If your pond is overcrowded, it is worth looking to rehome some fish. Koi need a much bigger water volume compared to many other pond fish, as they are known as being 'dirty eaters'. They produce a lot of waste per fish. Reducing feeding if you over-feed can be beneficial in reducing waste which in turn reduces the levels of nitrite and nitrate.
Another great way of reducing these nutrients is to introduce pond plants. These can utilise the nutrients in their growth, reducing the levels in the pond water.
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