My best friend has a large saltwater set up with clown fish and seahorses. It is EXTREMELY expensive for saltwater supplies- it all adds up quickly. Shrimp require lots of iodine and and other additives which cost a lot of money. Salt is about $80 for 100 gallons. Sand isn't cheap either and you need about 3-4 inches- sand costs around $200 for a deep sand bed. If you do not know your nitrogen cycle your animals won't be in the best of health because the water won't be at optimal quality. Corals require especial lighting which is expensive too- depending on which kind-it is around $150 ($50/bulb). Urchins are poisionous and will kill other animals in the tank along with you. You can only add one fish every 6 weeks so the tank can adjust to the new bioload from the inhabitants. Cycling the tank takes 6-9 weeks- which is required to keep the filtration up to par so the fish survive. If you do not cycle the tank the fish will die.

He spends a lot of time and money on his set up. LOTS and LOTS of research is a must- more than just reading some websites and books in a couple of days. Otherwise you are simply wasting your time and money.

Just thought I'd share....