New tank: nitrite won't drop down to 0

Michael43 · Dec 26, 2016

set up my new system about 3-4 weeks ago now. I set up up using 100% tds free RO water with live sand but dry rock. I seeded the tank using dr tims one and only and a fishless cycle. I watched ammonia spike to about 1.5-2 and from there nitrites went up to about 2 or so and have been holding at 1.5 or so for like 2 weeks now. Nitrates are about 3-5. 3 days ago I added 4 fish (2x 1" clowns, a 4" pyramid butterfly and a 1.5" 6 line wrasse) its about a 260-280g system so not much load with just these fish. I added them because the nitrite level is not dangerously high but I thought maybe the tank needs some fish pee and poo to help it get through the full cycle. Any help or advice would be greatly appreciated.

Brew12 · Dec 27, 2016

Michael43 said:
set up my new system about 3-4 weeks ago now. I set up up using 100% tds free RO water with live sand but dry rock. I seeded the tank using dr tims one and only and a fishless cycle. I watched ammonia spike to about 1.5-2 and from there nitrites went up to about 2 or so and have been holding at 1.5 or so for like 2 weeks now. Nitrates are about 3-5. 3 days ago I added 4 fish (2x 1" clowns, a 4" pyramid butterfly and a 1.5" 6 line wrasse) its about a 260-280g system so not much load with just these fish. I added them because the nitrite level is not dangerously high but I thought maybe the tank needs some fish pee and poo to help it get through the full cycle. Any help or advice would be greatly appreciated.

You are fine, you just have an unbalance in your bacteria. Dr Tims mainly uses Nitrospira bacteria that convert ammonia directly to nitrate internally. Your live sand probably provided a source of bacteria to convert ammonia to nitrite but a smaller number of bacteria to convert nitrite to nitrate. Eventually they will catch up.
Fortunately for us on the saltwater side of the hobby, nitrites aren't typically a problem. While they are extremely toxic for all fish, the same receptors that would absorb nitrites have a higher affinity for chlorides. Effectively, the salt in the water prevents the fish from absorbing nitrites and keeps them safe.

twilliard · Dec 27, 2016

Yuppers give it time, it will come down

Michael43 · Dec 27, 2016

Cool good to hear. You guys think it's ok to add more "hardy" fish? Ammonia is non existent for about 2 weeks now

Brew12 · Dec 27, 2016

Michael43 said:
Cool good to hear. You guys think it's ok to add more "hardy" fish? Ammonia is non existent for about 2 weeks now

I don't see it being a problem. I'm guessing you aren't quarantining your fish prior to adding them?

If not, just make sure you keep adding them very slow to reduce stress and feed a high quality mix of foods. You need to make sure they have a very healthy immune system if you go this route so they can fight off the parasites, like ich, that they are almost certain to be exposed to. Adding too many fish too quickly will be a stressor that you want to avoid.