Yes, it is a fish-in cycle. I mentioned in another thread that I learned about cycle after buying the tank for my daughter i have 6 week working with wc
to keep nitrites down. I already did the shake thing with the cartridge. The filter is a Tetra whisper 10i that came with a kit(I will never buy a kit again). I was thinking in buying a better filter but wanted first to know if there were possible to keep working with that one.