I am on day 19 of my fishless cycle on a 10 gallon tank. I used a ton of seeding material and up until now, I have not had a single nitrite reading. 4ppm ammonia was taking about 36 hours to get down to .5-1.0. In the meantime, I had tons of nitrates so I knew I was on the right track despite my lack of nitrites. 2 days ago I had a pH crash and had to do a 50% PWC to restore the buffers and stabilize the pH. I used Prime with my PWC, added my ammonia back up to 4ppm. The nitrates were down to 40. Yesterday was the first day I was able to process 4ppm down to .25ppm in 24 hours. I didn't test for the nitrites at the time because I assumed I would not get a reading as usual. The nitrates were around 80. Todays test showed I again processed 4ppm down to .25ppm in 24 hours but, this time I decided to test nitrites too. (API Master Freshwater) To my surprise not only did I have nitrites, they were likely reading off the chart. Def greater than 5. The nitrates were also back up quite high as well and I imagine tomorrow they too will be off the charts. I know my end goal is to be able to process the 4ppm into a 0 ammonia 0 nitrite reading within 24 hours. Im starting to wonder if something went wrong in the cycle with this sudden surge of nitrites. Best case scenario I will test again tomorrow and actually process the full 4ppm of ammonia AND show no nitrites but... what does it mean if I do end up with a reading of 0 ammonia and still tons of nitrites? Do I need to do yet another 50% water change already to bring the nitrites and nitrates back down into readable levels? Just when I thought I was on the brink of getting the fish in the tank, I run into yet another issue. I have read that too high a level of nitrite will halt the cycle. Is this true even with the existence of high levels of nitrates? How can I work on getting these nitrites processing as quickly as they previously were?