When I kick started the koi pond, I was peeing on the media ( not in public )
to give it a food source lol till it was ready as it was started from fresh. The bacteria will grow exponentially so all of a sudden one day there not there and then the next they are.
Take your time they will appear and if you must add fresh water then let it sit 24 hrs fot the chlorine and other additives to gas off.
One thing to check is that subject to your ph level the ammonia in the water can be toxic, so you may need to buffer the ph. It's the ammonia that converts to nitrites and then onto nitrates
Don't be in a rush