Sorry mate a bit grumpy earlier.............personally i wouldn't use sand but many do, ADA aquasoil seems to be the best available at the moment, its expensive though and im not sure of its availability in Australia, if you search through the threads there are many other options, laterite with a fine gravel is what i use ATM, and i have had good results with it, this is probably the cheapest option if you want a dedicated planted substrate, Seachem flourite and Carib Sea eco complete are other commercially available substrates that would also do the job but again its a question of whats available locally.
But use the search function its your friend on an information based forum.