Hello I am looking at setting up a marine tank but I am having trouble deciding on the correct tank setup to head down. It has been probably 20 years since I have kept marine fish and a lot of changed! Looking on the web it no longer seems like you buy your tank 3 foot 4 foot etc then buy a hood and your equipment to suit. Many shops seem to just have a ready to go tank with a cabinet.
What I have in mind is a tank with a few fish such as clowns, Gobys some live rock a few corals and a clean up crew. Can anybody offer suggestions of what tank I should be looking at? As in buy everything separate or buy a complete unit made by fluval etc?

I have in mind probably a 4 foot tank, but I already have a unit I would like to sit it on, so therefore I would probably use either a canister filter with a protein skimmer or a hang on the back filter. I notice that that there are always setups on eBay for sale but I think that this would maybe take away from the idea of setting the tank up from scratch.

Finally this may need to be a separate thread but it seems that RO water is almost essential to a successful setup. Is a RO unit worth looking at investing in?