just because you're not reading any nitrates, doesn't mean your cycle has crashed. if you suddenly have a an ammonia spike that doesn't go back down and no subsequent nitrites or nitrates, then you may have a disruption in your cycle. Even if that happens, its not the end of the world. You can always supplement your bacteria colonies by dosing with something like Microbelift Special Blend. I generally add that to any of my tanks after a more thorough cleaning or after I change out filter media.I cycled my 50 gal for 60 days before it was ready for my axolotl. It’s been consistently reading 0 ammonia 0 nitrites and 5 nitrates since I added him to the tank. From what I can tell he’s only pooed once. Weekly water changes approx 30% sand substrate. Hides and fake plant. Today test read 0 ppm ammonia 0 ppm nitrites and 0 NITRATES. I think I may just lose my mind, PLEASE HELP. Is my system crashed??? Do I have to begin cycling AGAIN???