I have a betta in a 10 gal that was cycled. I did a 20% water change on sunday and I am still seeing ammonia at .25ppm (my tap water is about 1 ppm to begin with). It seems like the BB should have converted this all by now. I did recently remove a spare piece of biosponge from the 10 gal to cycle a 29 gal...so maybe a minicycle? But also I was wondering how the BB colony stays alive with just one betta in the tank. Does it produce enough ammonia daily to support the BB? Stupid question I know because people keep Bettas in 10 gals, but just trying to understand.