I've been fishless cycling my 5 gallon tank with only 2.5 gallons for the past 6 weeks with temp at 86 F, gravel and a single air pump for circulation. I initially added enough NH3 to reach 4-5 ppm and then waited for it to start dropping. Once it did I reduced the daily amount to reach 3ppm. for at least 1 week after ammonia started dropping no nitrites were detected. It came to the point where I had to add enough NH3 to reach 3ppm twice per day in order to keep the bacteria consuming it all in 10-12 hours, which I'm still doing. I add enough in the morning to reach 3ppm, then test 12 hours later and it's down to 0ppm, so I add more NH3 to reach 3ppm and repeat the process. I've recently started decreasing the frequency of NH3 addition. Based on the results of my API nitrite test kit, the second bacteria being grown is not yet able to consume all the byproduct nitrites in 10-12 hours. Without any water changes yet, my nitrates are 160 ppm.