For the most part petcos tanks are not established more like holding tanks.. their rock is also diffrent then most "lr
" as like stated already I believe its just lava rock or other types that are similar sold as lr
just for the bacteria and nothing else. You don't need any live rock to start a sw
tank but imo
the best way to do it is build your scape out of baserock and then add one or two nice pieces of live rock and in a few months it'll all look the same. Usually the more pourous the rock the more hitchhikers you'll fine too as they have more hiding spots but don't underestimate all those little critters lol.. some people will go years without adding anything and one day something just "pops up" haha.