Why does nitrite block the cycle every time I start a new tank?

[Hans-Werner]

Google says: chloride ions block nitrite transport across fish gills but do not block nitrite uptake in nitrite-oxidizing bacteria.

Well, but the scientific articles say, NaCl inhibits nitrite oxidation, citations from the first linked article, CUI, Y. W., et al. Achieving biological nitrogen removal via nitrite by salt inhibition. Water Science and Technology, 2006, 53. Jg., Nr. 6, S. 115-122.:

"Microbial population tests supported the presumption that nitrite oxidizers are inhibited by salt addition and washed out of the system."

If google doesn't tell where it is citing from I wouldn't believe it. I would look for other scientific articles that confirm what I want to show.

Did you ask google why you have observed inhibition of nitrite-utilizing bacteria?

What's been preventing the nitrite-utilizing bacteria from taking up all the nitrite? They're either inhibited or no longer in the tank.

What was the answer?

Since it may be competitive inhibition, from a certain nitrite concentration upward nitrite oxidation may start. There may also be bacterial strains which can discriminate between better between nitrite and chloride or generally do better in saltwater.

I think there are also other kinds of nitrification but the nitrification by chemoautotrophic microorganisms, for example heterotrophic nitrifying microbes.

 

[Hans-Werner]

A quick search shows that the nitrite oxidation in marine environments is still under investigetion and not too much seems to be finally clarified yet, see here and here. This doesn't support the google response.

Citation from PARK, Soo-Je, et al. Expanded diversity and metabolic versatility of marine nitrite-oxidizing bacteria revealed by cultivation-and genomics-based approaches. Applied and Environmental Microbiology, 2020, 86. Jg., Nr. 22, S. e01667-20.: "Each enrichment culture exhibited a different tolerance to various nitrite and salt concentrations."