...but of course it'll take much longer to seed the base rock. The other thing you need to think about is that the more live rock you get, the more diverse the beneficial hitchhiking organisms. Many people find that a mix of gulf and keys/fiji rock is a nice mix that brings a larger repertoir of organisms that will help with natural filtration. I would suggest getting a minmum of 10 lbs of gulf and keys/fiji rock so you get the coraline and other creartures too.
Also, many places online won't let you order just 5lbs. They'll likely require a larger purchase of 20lbs or more. I can't speak for all vendors, but i know that the 'good' ones do this. IME
, it really depends on where you live. If you live in a coastal area that has lfs
teaming with life, get it from them. But where i live, the live rock is just a smidge above dead. So i got my stuff online where they require a minimum order of 20lbs or more. HTH