Help. Can’t get Nitrite <200ppb

[Dan_P]

Just to be clear, some of your nitrite tests say ppb and some say ppm. Are both correct where written?

Also, Hanna might be reporting nitrite- N, so you have to multiply the Hanna reading by 46/14 or about 3 to obtain nitrite concentration.

 

[Jimbo327]

Wait another 2 weeks. Don't buy any more bacteria. It's just marketing to buy more stuff you don't need. Your tank will cycle with time.

 

[cutter2001]

Hey guys. Noob here. I have a new Red Sea G2 Nano XL tank that started a fishless cycle on 01/23/26. Ammonia peaked at >2.5ppm with Nitrite initially registering at 11.2ppb on 01/25/26. Fast forward to today. Ammonia is .06 with Nitrite >200ppb after two 60% water changes. Last ph was 8.1. I continue to add Mycobacter-7. Latest Nitrite test after water changes tonight with Hanna blue box lab >200ppb. What am I doing wrong?

Update:
Nitrite measuring 97ppb! It’s finally <200ppb. Ammonia is .02ppm. Hopefully this will continue on a downward slope. Thanks for all of your suggestions and help.

 

[cutter2001]

Just to be clear, some of your nitrite tests say ppb and some say ppm. Are both correct where written?

Should be ppb. Sorry.

 

[cutter2001]

Just to be clear, some of your nitrite tests say ppb and some say ppm. Are both correct where written?

Also, Hanna might be reporting nitrite- N, so you have to multiply the Hanna reading by 46/14 or about 3 to obtain nitrite concentration.

It’s reporting NO2-N

 

[Randy Holmes-Farley]

Time to move forward. No need to wait to add your first organisms.

 

[cutter2001]

Time to move forward. No need to wait to add your first organisms.

What’s weird is last night I raked some of the sand just a bit, moved the media cylinders around, and this am I have what looks like a bacterial bloom. Water cloudy, etc. I have done that in the past and no cloudiness. Just wondering if that exposed some bacteria in the substrate to the nitrite and scant ammonia in the water, or if it’s just coincidental.

 

[sgdnycct]

Let your system settle down. Take the hands off approach. It’s a very new tank so minimal maintenance at his point. Looks like your cycle is complete but not stabilized. Give it another week hands off (including time for the cloudiness to clear). PS the cloudiness could just be the fact that it’s a new sanded so it contains dust (I’m making some assumptions here).

 

[Randy Holmes-Farley]

What’s weird is last night I raked some of the sand just a bit, moved the media cylinders around, and this am I have what looks like a bacterial bloom. Water cloudy, etc. I have done that in the past and no cloudiness. Just wondering if that exposed some bacteria in the substrate to the nitrite and scant ammonia in the water, or if it’s just coincidental.

I doubt it is likely coincidental, but I also don't think it tells you anything useful.

 

[dvgyfresh]

Nitrite is usually not concerning , I have had it in my tank since July 2025 setup , I think recently it has gone down but no adverse affects , I also started with all live rock

 

[Dan_P]

What’s weird is last night I raked some of the sand just a bit, moved the media cylinders around, and this am I have what looks like a bacterial bloom. Water cloudy, etc. I have done that in the past and no cloudiness. Just wondering if that exposed some bacteria in the substrate to the nitrite and scant ammonia in the water, or if it’s just coincidental.

More likely a micro algae bloom. Aquaria probably don’t accumulate much labile organic matter, the kind that causes a bacteria bloom, because it is almost impossible to keep bacteria from devouring it. Inorganic nitrogen can accumulate to some extent in the sand. Stirring the sand could have released enough to create a temporary growth spurt of micro algae. Of course, stirring sand can release fine particles that can cloud the water.

 

[Lasse]

Have you continue with your addition of Mycobacter-7? If so - its a likely source to your cloudiness - IMO

Sincerely Lasse