As the title states, I have a 10g tank that has been cycling with 3 zebra danios and I have yet to see any nitrites or nitrates. My ammonia levels have been between 0.5 and 1.0 ppm. I am using API freshwater master test kit to test water every 3 days or so and doing 20% water changes every 2-5 days to prevent ammonia from spiking too high. Also, since I'm getting close to having run this filter cartridge in my power filter for a month; should I change out the filter in a week or keep it in until my tank is cycled? If you need anymore info, just ask. Thanks in advance.