The OP was smart either way in this regard. The question here is does rinsing rock affect nitrification right? Well - the first part of the study will prove whether he has enough surface area or not. If in the first part - that rock processes ammonia - there is enough surface area - if it does not - then there is not.
The comments about needing 5 x the surface area to do a 'rip clean' to me do not make sense.
Yes, I'm performing the first part to make sure there is enough bacteria present to process the ammonia in the first place. That was the point of it more than proving you can instant cycle a tank with rock and biomedia.
If I had gone straight to the tap water we would never know if there was sufficient bacteria present to begin with.