On both of my < 1 yr old tanks, I established nitrification bacteria in dry aragonite substrate prior to receiving GLR. There was no ammonia spike when I added live rock. I choose not to add fish who grazed on new sprouts, to further evaluate what I wanted, not what survived the CUC. Urchins, crabs along with rabbits & tangs are aggressive grazers which can be added when needed. I prefer to be the first curator.
First two pictures are 55G & 30G both at 11 months young. Last picture is 25 year mature 75G tank with some GLR from 11 months ago that have gorgonions and red tree sponges emerging. Excuse dirty glass, it’s Spring garden planting time.