Occasional barely detectable nitrite (Cycling done and fish in)

[MDDad]

Did a fishless cycle. Added fish Sunday the 4th.

Twice daily, I'm doing a nitrate and ammonia test, just to check on things.

Ammonia is always zero. Nitrite was zero both times Monday and Wednesday. This morning (Thursday) and Tuesday morning, I got barely detectable levels, a slightly darker blue than the zero reading on the API kit, but nowhere near lavender enough to be 0.25. So I classify that as "detectable but negligible."

Tuesday evening it had returned to zero. I will check tonight as well.

Are those barely detectable levels harmful, and is it normal to have a very very mildly detectable readings from time to time?

 

[Caliban07]

Did a fishless cycle. Added fish Sunday the 4th.



Twice daily, I'm doing a nitrate and ammonia test, just to check on things.



Ammonia is always zero. Nitrite was zero both times Monday and Wednesday. This morning (Thursday) and Tuesday morning, I got barely detectable levels, a slightly darker blue than the zero reading on the API kit, but nowhere near lavender enough to be 0.25. So I classify that as "detectable but negligible."



Tuesday evening it had returned to zero. I will check tonight as well.



Are those barely detectable levels harmful, and is it normal to have a very very mildly detectable readings from time to time?

Nitrite toxicity will result in fish gasping at the surface with possible red/brown gills. If your fish are not doing that then they are fine.

 

[MDDad]

They seem perfectly happy.

 

[Caliban07]

They seem perfectly happy.

That's good. Also chloride found in tap waters will also have some level of protection.