I have had my 20 gallon high freshwater tank set up since August 16th, and added ammonia 4 weeks ago. I had been using Seachem Stability but I was testing for Nitrites and never saw any. 5 days ago I bought and used Tetra Safe Start Plus directly into the filter, attached a sponge over my intake filter, and put extra media into the filter. Yesterday I tested Nitrites and saw none and decided to just test Nitrates and to my surprise it was between 5-10ppm. My ammonia had been around 4ppm and now it is between 1-2ppm. Is it possible that my tank could have cycled without me seeing Nitrites? If it is, will my ammonia continue to go down to 0ppm?