Yes if you start from scratch, no, maybe if you use live rock. Get enough live rock, in good enough condition, and there's theoretically none as it comes with a fully working set of diverse bacteria. Not sure about sand though.
Really. Depends on how much dieoff I suppose, but you should have a full set of bacteria from day one. I guess you need to wait for it to faill into equilibrium with the waste load you apply. Define finishing - 0 ammonia, nitrites would be definition
