It is day 41 of my fishless cycling and my nitrites are still high. I've been cycling my 10 gallon with pure ammonia. I added about 5ppm of ammonia to start off and kept it there until the nitrites spiked, which happened on day 18. After that, I added enough ammonia each day to keep the level at about 2-3ppm. The ammonia level consistently fell to 0 after 24 hours but the nitrites showed no sign of decreasing. The nitrates weren't increasing either, they remained at about 5ppm. I've been using the Nutrafin Liquid Test kit for nitrites and they have been off the chart this whole time. In fact, once the dye had been added the liquid would turn yellow after about 4 minutes. It is supposed to be a shade of magenta.
Yesterday, I decided I must have done something wrong and did a water change of about 75%. I filled up my five gallon buckets with old tank water, dumped them out in the bathroom and refilled them with new tap water. After the tank was refilled I tested them again and found the nitrite levels to still be off the chart. Confused, I went and refilled the same five gallon bucket with water and tested the water out of the bucket for nitrites. They were very high. When I tested the water out of the sink the nitrites were zero. Is there some way that a large number of nitrites remained on the bucket that had had the water from the fish tank in it? I followed this up with a water change of about 90%. I didn't use the buckets for new water this time but instead filled a one gallon carton with water and carried it back and forth between the bathroom and my room. This time the nitrites registered at 0.3ppm. I added about 2ppm of ammonia and went to bed.
This morning, I woke up and tested the tank again. The ammonia was almost zero and the nitrites were over 3ppm. I did an 80% water change and filled the tank up with water using the 1 gallon carton again. The nitrites were at 2ppm when I finished.
What am I doing wrong? Why won't the nitrites significantly decrease even with large water changes? I really want to move my betta into the tank since he is in a 1 gallon right now but I need to get these nitrites under control.