cant get nitrite down to 0

acr0p0ra · Jan 30, 2018

Hi,
I have a 125 gallon system that I bought used. It has been running for about 1 month.
ammonia is reading 0 and nitrite is constantly reading .25. There are 3 small fish in the tank. No live rock but there is sand and a biological media block made by Marine Pure. The system is being used for QT.

I have added several bottles of bacteria to it and I still cant get the nitrite down to 0. is it possible that it is locked into the plumbing or pvc? seems unlikely but I dont know what else could be causing it. I have done 50% water changes and it still stays at .25. I tested with API and Red Sea. It doesnt go higher than .25 ever. Nitrate is 0.

There is no skimmer on the tank. The tank has been medicated in the past, not sure if that matters or not but I can tell because the silicon tubing that I removed was blue im guessing from quick cure

any suggestions?

Randy Holmes-Farley · Jan 30, 2018

It might be test error. Or it might be real. In any case, it's not a concern and I'd just stop testing for it.

Nitrite is not toxic in marine systems the way it is in freshwater systems.

This has more;

Nitrite and the Reef Aquarium by Randy Holmes-Farley - Reefkeeping.com
http://reefkeeping.com/issues/2005-06/rhf/index.htm

acr0p0ra · Jan 30, 2018

interesting articles. thanks for sharing

I dont believe the test is inaccurate because i have tested it on 3 other identical systems and they all read 0 with both kits.

Randy Holmes-Farley · Jan 30, 2018

acr0p0ra said:
interesting articles. thanks for sharing

I dont believe the test is inaccurate because i have tested it on 3 other identical systems and they all read 0 with both kits.

OK, although I have also heard of many folks with issues with the API nitrite kit.

In any case, the actual value is unimportant.

PatW · Jan 30, 2018

You might pick up some Dr. Tim’s bacteria cycling stuff. I used it on my first cycling. Dr. Tim’s seems to have a pot load of bacteria that convert nitrite to nitrate. On my first cycling, I only saw a little nitrite for a day or so and then 0 even though I added ammonia several times.

I just cycled another batch of rock and this time I had quite a bit of nitrite build up. It took a fair amount of time for nitrites to go to zero. Of course with enough time, the bacteria to convert nitrites should build up.

If it bothers you, pick up some Dr Tim’s. But like Randy says, a little nitrite probably won’t hurt. And eventually, the bacterial fauna will deal with them.