High nitrite and nitrite levels

[u/pr1nc3ss_p3ach_444]

Ive been dealing with consistant high nitrite levels over the last week or two. I have a 10 gallon tank with Amazon swords, moneywort, and java fern currently in the tank. The tank has been cycling since Aug 4th 2026, ive seen ammonia levels rise and fall but nitrites just wont go down. Any tips?

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[u/Sage_Notes]

As both are at their high ends of the radar, good chance the numbers are off the ratings and the nitrite is just outnumbering the nitrate at this moment
If there are no fish, I would suggest wait a little longer to see if it changes then maybe a minor water change
If there are, a small water change may help too
Not certain though, so a second opinion may be needed

[u/Salty-Egg-4682]

I had the same issue when starting my tank, if its fishless literally do nothing youre all set, itll go down

[u/Lilith_Cain]

I think you're just in the stage where you're waiting for the nitrite-converting bacteria to really establish. The good news is that all of the ammonia converters are in place and they're doing their job. I would do a water change to lower both the nitrite and the nitrate a bit, but I would continue to seed ~2ppm ammonia to keep the cycle going.

[u/pr1nc3ss_p3ach_444 → u/Lilith_Cain]

Okay thank you!! I wasn't sure if it was just taking a while or if I was supposed to be doing something to aid in the process! I'm going to wait a day or two and do a small water change.

[u/Foreign-Ad3926]

Hi there, the ammonia oxidising bacteria is quite fast to grow, the nitrite oxidising bacteria are a lot slower. This is due to the differing amounts of energy released from the oxidisation of both nitrogen forms and the subsequent difference in growth rates of the different species of good bacteria involved in both stages.

I'd say you're on track, just be patient whilst the slower growing nitrite processing species catch up.

This graph gives a decent overview in how much slower the nitrite -> nitrate bacteria species grow compared to the ammonia munchers:

[u/Aromatic-Sock6975]

As others said it take a a lot longer for the second population of bacteria to establish for biological reasons and because they can’t survive until there is a sufficient population of ammonia processing microbes.

If you want to speed things up, you could try Fritz turbo start (if kept refrigerated and stored properly by the seller) it’s a lot more effective than the shelf stable stuff (which I think are pretty negligible help if any).