ive started a 30 gal tank and currently 3 weeks in on a fishless cycle, ammonia is down to 0 ppm, nitrites are 5 ppm and nitrates were 150 ppm. After two water changes within 48 hrs i got my nitrites down to 2 ppm, my nitrites are right back up to 5ppm and my nitrates are at 40 ppm. I've added ammonia twice since starting and have gotten the bacteria to process ammonia within a 24 hr period. I've also added dr tims twice. Did I stall my cycle?