im probably gonna say what every1 is thinking with this,
if you are spending the time and money to build a 730gal tank dont cheap out on the accessories..... mainly because you will probably have to redo it all agian very soon.... filtration you might be able to use like a large pond or above ground swimming pool filter but will probably need other items to help filter, heating you could also probably use a small pond or pool heater... i have seen a few DIY heating systems.... and lighting i would guess you could find on Ebay or Craigslist......
thats just my .02