I just went threw this exact same thing the past few days. I had my tank mini cycle right after I got my rays on Saturday. I successfully beat it by changing 20 gallons a day since it's a 220 gallon so approximately 1/10 of the tank volume every day. I also cut back to one light feeding a day to slow the ammonia output of my fish. I also forced my intakes to suck in the crap from the dead spot in my aquarium where crap collects and doesn't get sucked into any of my three intakes. The theory behind this is that I have the bacteria in my filters but it isn't sufficient enough to keep up with the tank so like all things to get them to grow you have to feed it right? So I didn't siphon out any crap for the past four days and simply siphoned out water and forced my intakes to take in all the crap so it would feed the bacteria in the filters. So yesterday I decided to do a second 20 gallon change 12 hours after the normal 20 gallon water change to hopefully accelerate the ammonia reduction. Then today I decided that I am too impatient and I wanted to dose with prime because I am too impatient for my own good and I know that prime would help but before I decided to add the prime I figured I would test my water just to see where I was with ammonia (because I personally hate adding anything at all to my water if I don't absolutely have to) and my test came up with 0 ppm even though yesterday before my second water change I was at .5 ppm which came down from my highest of 1 ppm. So no believing I did the test correct, I retested the water 4 times to confirm that it actually was 0 ppm and all four tests came up with 0 ppm. So I succeeded in cycling my 220 with two rays and three 7-9" ntts in four days and going from 1 ppm to 0 ppm in only four days without adding prime. I hope my experience helps and good luck!
Sent from my iPhone using MonsterAquariaNetwork app
Sent from my iPhone using MonsterAquariaNetwork app