View Full Version : very strange cycle

fish speaker
12-16-2004, 09:54 PM
Nothing earth-shattering here, just something that has me curious. I am cycling a 75-gallon tank, which I dosed with Bio-Spira. I'm doing a fishless cycle (I know, they say you can just plop the fish in with Bio-spira, but it didn't seem prudent to me). After watching the ammonia spike, followed by a nitrite spike, I was expecting the ammonia to drop off pretty quickly. It has started down, but tonight's water testing showed that the nitrite level has dropped dramatically. To make sure I didn't imagine it, I tested nitrates, and they are sky high. As long as it cycles, I'm happy...I've just never had a tank where the nitrite levels dropped off before the ammonia levels did. Is it the Bio-Spira? (This is the first time I've used this product).


12-16-2004, 11:30 PM
It might have been. From what I've read, the fishless cycle technique causes the Nitrobacter that process the Nitrites into Nitrates to die off when ammonia levels are high. This makes the second part of the cycle go slower since these are usually killed off in the process and need to be seeded after ammonia drops. I've never used the bio-spira either but from things I've read just here in the last couple of days, it sounds like a good product. It could be that it contains Nitrobacter that didn't get killed off in your cycle.

For what it's worth, my latest cycle had three days where the nitrite was dropping before ammonia dropped to zero. Details are available from my website link above.

Good Luck.

12-17-2004, 09:07 AM
the thing about bio spira is, you should add fish soon after you put it in the tank (within a couple days?) because you need the fish in there to produce the food in which the bacteria feeds on

(at least, this is what my boss at the lfs told me, which is what marineland told her when she called them about it.)

fish speaker
12-17-2004, 12:48 PM
I started "feeding" it clear ammonia the same day I dosed the tank. It has cycled fairly quickly, just not instantly...and the nitrite dropping before the ammonia was the first time I had seen that happen. I'll just accept it as a nice surprise that I don't have another week or so to wait for nitrite reduction. :D

12-17-2004, 02:17 PM
Yep, mine was relatively long. I let the ammonia spike too high early on in the cycle. This is the hardest time and patience is at a premium. Good Luck!