James_in_MN
Aquarium Advice FINatic
eco23 said:Yeah, I remember taking part in the thread. While it was interesting, I think its a totally different situation than here. For one, you were in the process of fishless cycling where you were adding 4ppm of ammo per day, the cycle was not complete and you had no2 present in the tank when you left. A fishless cycle at 4 ppm is designed to grow a huge amount of BB, which is not equal to a cycled tank where the bio-filter has adjusted to a actual stocked level. Also because you were mid-cycle and had no2 in the tank there was plenty of food remaining for no2 to no3 bacteria to continue colonizing while you were gone. I'd assume there was plenty of bacteria die off, but since a fishless cycle grows such a massive bio-filter and they really hadn't gone that long without food (4ppm ammo before you left and no2 remaining) there was still BB remaining to continue the nitrogen cycle.
That's actually not quite accurate. I said I was mid-cycle because I was dosing ammonia and had nitrItes (NO2) around 4ppm-ish. If I had ammonia with no nitrites, I would consider that to be the beginning of my cycle, not mid-cycle.
And yes, there's no way of knowing when the nitrIte spike subsided while I was gone; all I knew is that all ammonia and nitrItes were consumed when I returned.
I understand that we build up a large biofilter when we fishless cycle, but ammonia was disappearing about as quickly as it was when I left for the conference (around 1 day).
eco23 said:The OP had a stocked, established tank with a much smaller colony of BB. When the fish were gone...the nitrifying bacteria were instantly deprived of food.... no one last big dose of 4ppm ammo, no remaining nitrItes. While some decaying organic matter might have provided some sort of food source, I can't imagine it sustaining them to a level that would keep the tank considered cycled. I think it would have very quickly become a fish in cycle if the tank was simply restocked because the tank was considered cycled.
While it may be a smaller biofilter, I still think it would have at least been worth a test to see if there was any bacteria left. Again, there is limited information on how long nitrifying bacteria will live without a food source.
eco23 said:Regardless, the OP will be fine since she has the 55 gallon filter, I just think it's a dangerous precedent to let people assume a tank will stay completely cycled after a month. I still think the reason it read 0's with remaining no3 is simply because anaerobic bacteria had not converted the nitrAtes. At the very least, the tank should be tested with pure ammo to see how much ammo it can convert to no3 in 24 hours before we assume anything.
That's exactly my point. Why not run a test just to see if there is anything left of the biofilter?
And no, I'm not looking to set a precedent or create assumptions, but there is an assumption that all the bacteria is dead, right? Why not see how true that really is?