I am trying to figure out why am I seeing ammonia spikes in a new fishless tank.
About 2 weeks ago I set up a 20 g long with the intent of keeping low light plants and shrimp in it.
I am using about 30# EcoComplete, Finnex 100w heater, AquaClear 50, and Aqualight dual T5 NO. I transferred the sponge and extra ceramic rings from a filter in an established tank. Most of the plants are from an established tank plus some new ones. Root tabs, flourish comprehensive and excel added for the plants.
After the initial cloudiness from the substrate, things cleared up for about a week and a half. I am using polyfill in the AC. Did not test the water or do any water changes.
This past weekend the water looked as if someone poured a cup of milk in it and i figured it was a bacterial bloom. I assumed that there would be some ammonia present when the bloom peaks and crashes. It cleared up in about two days so I tested the water and got Ammonia 8+, Nitirites 0, Nitrates 5. Did a 90% water change and tested the next morning: Ammonia 1.0, Nitrites 0, Nitrates 5. Then I tested it 24 hours later and I see Ammonia 8+, Nitrites 0, Nitrates 0. Huh?
Nitrates going to zero is probably due to the plants; zero nitrites means the cycling has stalled or is non-existent; but the ammonia has me stumped. I am not intentionally adding ammonia to it. I tested the water and it was zero for ammonia, nitrites, and nitrates.
Where can the ammonia be coming from? I have a moss ball from the established tank...maybe that is the source? But while it was in the other tank the parameters were stable. Also, under the hill on the left side is half a red brick. I was concerned about anaerobic activity since the substrate might be 6" deep there so I put a half brick there. Brick was in the back yard for years and was not used with cement or mortar. In hindsight, due to the porous nature who knows what it has absorbed while it was outside. pH is 7.4. I will be taking it out tonight and doing another big water change and then retesting 24 hours later.
Any thoughts on this?