Update: Crazy Cycle

[tsonnenl]

I started cycling my 72 gal tank 5 weeks ago with a dozen zebra danios who are fed flake food once a day. I replace ~20% of the water every week. It seemed to be going slowly at first, with ammonia not appearing in significant levels until week 2 or 3. I admit to only testing the water about once a week, so it may have occurred sooner than that. The highest I saw NO2 levels reach was 0.2 ppm at the 4 week mark. Around that time I added Biozyme to try to accelerate the process, and now I don't know what I have. I still have 0.25ppm of ammonia in the tank which doesn't seem to be going away. NO2 levels have dropped to zero, and NO3 levels have never left zero. I'm sure I'm screwing myself by not testing the water more, but where the heck am I in the cycle now?

Thanks in advance,
Todd

 

[Guest]

OK, deleted the double post 8)

I would stop changing water for 2-3 weeks, and test more often, prolly every other day. I think the cycle has been slowed by the water changes. Also, a 72 gallon is a big tank, and zebras are little fellers, so the cycle will take longer. You are on the right track though, don't worry!

 

[Bearfan]

I agree with everything corvuscorax said, but a dozen danios is PLENTY to cycle a 72 gallon tank. I agree you are on the right track, just cut back on the water changes and let the cycle work.

 

[tsonnenl]

Ok, two weeks later, no water changes......no change. I have even increased feeding them from once a day, to once or twice a day. Ammonia 0.25ppm, Nitrite 0, nitrate 0. This tank was set up around April 26th! This water is invincible.