Nitrite is produced by the beneficial bacteria in the pond and filters as they break down the harmful waste ammonia excreted by the fish. Regularly taking accurate and reliable tests is very important because any nitrite present in the pond will be very damaging to the health of the fish.
Toxic nitrite can build up in ponds where there are not sufficient beneficial filter bacteria to deal with the total waste from all the fish in the pond. This situation can arise in new ponds, when new fish are added, when the filter bacteria have been disrupted (eg. during cleaning), or during accidental misdosing of pond medications.
How do I take the test?
Ensure the test tube is clean. Take a 5ml sample of pond water into the test tube, preferrably using a hygienic Easydip Water Sampler. Add 5 drops of the Nitrite reagent. Replace the test tube cap and mix. Wait 2 minutes, then compare the colour of the sample to the colour scale provided. Zero nitrite is represented by a colourless sample. Any hint of pink in the sample indicates the presence of nitrite in the pond. Any colour forming after the two minutes should be ignored.
What do I do if the nitrite level is wrong?
If a level of 0.25-0.5mg/l (PPM) is recorded then add a filter booster such as NT Labs Koi Care Filter Bugs or Koi Care Actizyme. If a level above this is recorded then a substantial water change is essential. Change 25% of the pond volume for a level of 1mg/L (PPM) and 50% for nitrite levels above this. Koi Care Pond Zeolite Chunks and Koi Care Pond Aquazorb will remove ammonia (and thus nitrite) from pond water and can be recharged. If you do record a nitrite level in your pond, then it is important to check other vital water quality parameters, especially oxygen, pH and ammonia.