Cycling Question

[gems]

Hi

We’re in the middle of a fishless cycle with our 16 gallon (UK) tank, we followed the Add & Wait method in rdd1952’s fishless cycling post. Our tank now goes from 3 - 4ppm down to 0.25 ppm in around 12 hours. The nirIte readings are staying at 0. The concern I have is that it takes another 12 hours for the ammonia to go from 0.25ppm down to zero. Is this normal? I would have thought that if it can go down from 3 – 4 to 0.25 in 12 hours then it should get to zero fairly soon after that. Is our tank ready for fish yet, or do I need to wait until the ammonia is reaching 0 within 12 hours? The reason I’m asking is that further down in rdd1952’s post is says “Once it drops to 1 ppm raise it back to 3 or 4 ppm. Do that everytime it drops back to 1 until the nitrite finally drops to 0 and then your done. Do the big water change and add fishâ€￾. This has happened in our tank I think, it’s just that the ammonia takes the extra time to drop form 0.25 down to zero. Any comments would be great, Thanks

 

[gems]

anyone? Or have you all been watching the England match like us?!

 

[Tokis-Phoenix]

Don't have much experience with fishless cycling personally, but i would avoid adding fish until ammonia and nitrites are 0 since both of these stats are toxic to fish.
Someone with more experience with fishless cycling methods should come along soon to help you out hopefully though .

 

[gems]

Obviously we realise that levels of either ammonia or nittire are toxic, and our readings show 0 nitrites and 0 ammonia, it's just that the ammonia takes 12 hours to go from 4ppm down to 0.25, but then a further 12 hours to go from 0.25 to 0. According to the pinned posts on fishless cycling, our tank will be cycled when the ammonia goes from 4ppm to 0ppm in 12 hours. We are just wondering why it takes so long for it to go from 0.25 to 0 when it takes the same amount of time to go from 4 to 0.25!

 

[Tolak]

If the ammonia drops from 4 ppm to 0ppm in 24 hours, with no nitrites, I would consider it cycled. That is how I've done the tanks I've cycled fishless.

 

[gems]

Excellent, thank you for the reply. We figured the tank was about ready and capable of coping with fish waste if it was going from 4ppm to 0 in 24 hours. Now we can go get our first lot of fish!

 

[Edge]

So does that mean the tank can now be fully stocked? Or should the ammonia be dropping in 12hours for that? How much ammonia does a tank full of fish produce in 24hrs? I know that's a hard question to answer, but say you were feeeding reasonable amounts twice a day and all the fish were adults. Is the amount to add to a fishless cycle 4ppm for that particular reason?

 

[mark.w.jones]

Fishless cycling produces a huge excess of filter bacteria, far more than a fully stocked tank. Ammonia from 4ppm to 0ppm in 24 hours is what seems to be agreed in most articles as you having enough bacteria to cope with all fish waste that will be produced in a full tank. I fully stocked my whole tank the same day as my 100% water change but I know other members have been a little wary of doing this. I only suffered 2 deaths so cant imagine it did any harm. I would say you need to be fully stocked within 3 days at most though as excess bacteria with nothing to live off of die quick.