Well first off, you probably don't want to use oyster shells. There are many places to order dry rock from. Bulk reef supply, reefrocks.net, just to name a few. Your LFS
should have dry rock fairly cheap. About 1 lbs per gallon is normal. As for salt. You can get that online or at most pet stores. Petco has cheap salt. Most LFS
offer premixed water if you prefer that. I prefer my ro
. Water maker and mix my own water.