Nitrite

As your tank goes through its initial cycle, nitrite starts to show up right after the ammonia spike. We know why this occurs because; the bacteria starts to develop as soon as ammonia is on the scene.

Ammonia is very toxic, but it would seem from all the research I have done that nitrite is far less toxic than first believed. The main problem is that if it is present in your reef aquarium, ammonia must be present as well, or it was present a short time before.

As your reef tank matures these levels find a balance. When you test for them, usually the test will show zero. This simply means that both are being converted by bacteria as fast as they are being made. That’s the balance you want and need for a healthy aquarium.

Should you test for this?

That’s a good question. Consensus seems to lean toward testing during your initial cycle but after that period, there is no need to test further. I must admit that I only test for it during the cycle period.

Studies have shown that fish can survive in sea water with levels over 100 ppm (parts per million). The same cannot be said for corals and invertebrates. I wouldn’t want anywhere near that level in my aquarium. After the initial cycle you should have a zero reading in your tests.

If you do detect high levels, something over 5 ppm, then you may have something dead and decaying in your tank. Take a good look in your aquarium and do your best to remove anything that appears to be dead. It might be a good idea to perform a water change to help lower the toxic levels.

If you are having any problems with your tank, it might be a good time to add this test to the rest of the tests you are doing. Test kits for this are readily available at most marine fish stores or from an online store. They are relatively cheep and work quite accurately.

At least it could eliminate it as the cause of a problem.