If you're not doing corals its not really a reef but Fowlr
. If this is the case RODI
water isn't a must, distilled water will work just fine. I would avoid tap water though some do use it. Live rock is not necessarily straight from the ocean, it only refers to the rock holding the beneficial bacterias that make the tank "cycled". Sniper hank is right (as always) if you're not going to buy live rock you must cycle the base rock using an ammonia source such as shrimp prior to adding live organisms, that was my method per his advice. I run a hob
filter as well as power head, though I can't speculate whether the hob
is neccesary, I like it for the ability to run purigen. A tank this small is prone to dangerous swings making it difficult to maintain, bigger is better in SW
All that said if you're going to have to skimp on basic equipment you need to hold off on a saltwater tank, its an expensive and involved endeavor and the cost doesn't end once all the equipment is acquired.