fishbum

I started out cycling 2 tanks,a 10 and 30 gallon.In the meantime of these cycling,I bought a 120 gallon.They were all cycled with shrimp for the ammonia source.The 10 and 120 have completed the cycle.I thought the 30 was right on track with the other 2,but when the 30 gallon's ammonia level dropped to 0ppm,the shrimp had completely decomposed,so I started to use flake fish food for the ammonia source(and still am),this happened in the 10 gallon also(not in the 120).Why would the 10 &120gallon finish the cycle,but the 30 now has ammonia in it again,25 to 50 PPM,depending on the day.The 10 gallon and 120 both have fish in them now,for a week now,and both levels are 0ppm ammonia and nitrites,and 10 ppm for nitrates.I won't add any fish to the 30 until it is 0ppm for the ammonia,again.I have 2 HOB filters,with bio wheels, on each of the 10 and 30 gallon,so I have taken one out(HOB) of the 10 gallon and added it to the 30.I know with the bio wheel on it this will help finally end the cycle,but why did this happen?

Any ideas?

Wolfgang8810

sometimes the cycle can collapse if not enough ammonia is present like you said the shrimp completly decomposed and the bacteria in the nitrogen cycle die every 24 hours so they might have starved. id wait for other fishloreans though