best thing to do is buy the rock live.
http://www.trademe.co.nz/Home-living/Pe ... 831396.htm
make sure you know what you are getting yourself into...
ontop of the increased prices for lifestock there is also costs involved in; skimmers, test kits, Metal halides, extra electricity, refractometers, sumps, powerheads, return pumps, RO units chemicals etc....
the day to day care and upkeep of a sw reef tank is also much higher than a fw tank too...
Its a great hobby but just make sure you have the cash to give your fish and invertebrates the best possible home...