If you have any coralline in the tank, even on a snail shell it will spread. Just keep the water clean and provide some light and it will spread pretty quick.
I just set up my 180g about 2 months ago and had some coralline covered snails and one rock with it and its now growing on other rocks as well as the glass,
180g- Mostly BIG fish and some coral. ~80g Nuvo- My coral tank with "happy fish"~ 90g- FOWLR Not the not happy type of fish~ 125g- Freshwater Malawi Cichlids ~10g- Nuvo- The refugees from the Ich of '18