nitrite

[makana]

I have a 10g nano that has been setup for about a month and a half. The only livestock is some snails that came on the live rock a small hermit crab and a small mushroom frag.

The cycle finished about 2 weeks ago. About one week ago my nitrite came back up to about 0.1ppm. No other levels changed. I check daily and the amonia has always been 0. I find it strange that it came up and stayed up.

Last night I checked the levels on my fresh water tank and had the same nitrite reading. The fresh water has been up for almost 2 years and has never had nitrite since the cycle finished back in the day.

Is it possilbe that the kit is bad? Or maybe the test tubes are dirty and causing this reading? I have new regents I could open up and try but no new test tubes. The kit hasn't met its expiry date yet.