Ammonia spike

[Smeola]

Hello!

I have a 6 month old 100 gal FOWLR with a 30 gal sump/refugium with an in sump skimmer, a small macro algae population and mangroves that have small roots, and no leaves at this time. I currently have 4 fish (3 chromis, 1 fire fish) and a small CUC.
I thought my tank was done cycling as my ammonia and nitrites went to 0 with low nitrates (after a few weeks of them all being high). That was the beginning of Nov. I was continuing 10-20% water changes and working on getting the nitrates lower (they have been ~10-20 ppm range recently) before adding more inhabitants. The last 2 weeks I have had an increase in ammonia (0.2-0.3 ppm), with no change in nitrates and I continue to have no nitrites.

Here is my question: if I have ammonia doesn't it have to be converted to nitrites on the way to nitrates? Can I have high ammonia with 0 nitrites? I am sure it means the tank is still cycling and not stable yet. Any suggestions, or just more patience. Thanks for the help.

 

[Russellaqua]

You're right in that ammonia must be converted to nitrite before another conversion produces nitrate. In a system that is constantly being supplied with ammonia (like any tank with fish in it) there will always be some nitrite. Our test kits generally don't have the ability to detect the very low levels of ammonia and nitrite present in the cleanest of tanks. As to why you aren't seeing an increase in nitrite, I'm not 100% sure. Your nitrite kit might be bad or your levels could be below the kits' detectable lower limit. If the ammonia is being converted slowly you could easily stay at low levels of nitrites, and this wouldn't make for much of a change in your nitrates either. How much rock do you have, and is it porous?

 

[Smeola]

Thanks for the thoughts. I have about 50# of LR that is porus. It is a standard substrate deep sand base. I do also have de*nitrate gravel in a bag in the sump to try to help with the nitrates. I guess it is possible it is also binding the nitrites to keep them below my level of detection. I test with both an API and nutrafin test kits to try to avoid kit errors, and compare the results. I will give the tank more time and try to be patient. Thanks again. I suspect I am over feeding as the cause of my ammonia increase.