Hi, just setting up my first aquarium and currently doing a Fishless cycle. Everything going well so far, ammonia added to 4ppm and this morning down to 0ppm. Nitrites greater than 5ppm and nitrates at 10. I have just added more ammonia to take it back to 4ppm. I know that the good bacteria needs to feed on ammonia but how long can they survive without any? Can they survive a few days without any?