hey chris
good on ya first of all
in auckland you have heaps of people that can help you out
you should look at going to steves on sunday if you can, that way you can meet a lot of people to help you, have a look at a nice tank and get ideas for yours, he also has a tank with live rock to sell
as for the sand, dont get stuff from the beach unless your setting up for a native tank (even then watch out cause of the silicates in it and other unknowns)
come on over to the marine section when your ready