Originally Posted by Jawaits
Get dr tims one and only it's amazing and it instantly cycles the tank
Dr. Tim's One and Only might speed up a cycle, but it doesn't instantly cycle a tank. I'm using it now in my 75G, and while it seems to have sped things up, my tank was NOT instantly cycled after adding it. The day after my nitrite was around 5 ppm
(it's a fishless cycle), and it took about 3-4 days for it to come down.
Edit: just as a little add on, my nitrite level of 5 ppm
probably would've killed any fish I would've had in there. Again, a little patience will go a long way.