well a saltwater tank would usually need a protein skimmer if u plan on keeping corals, anemones, and other invertabrates. u would probably need to test lets say..once a week. u should continue changing about 10-20% per week, and u need to mix the water with the salt the day before maintenance day-it can be pretty caustic when freshly mixed. many people use live rock as biological filtration to save money (though we don't). if u don't use live rock, canister filters(we use fluval)and corner filters(ours r filled with angel hair cotton, activated filter carbon, and riverstone 4 wait.)work well for our 125 gal saltwater, along with 2 powerhead/filters. if u know someone else who owns a SW tank, ask them 4 a bit of their substrate 2 cycle your tank. otherwise, u either use live rock(it cycles the tank while it's curing.), commercial chemical products(check around the internet 2 find ones that work), fish(blue devil damsels and other similar devil damsels and chromis do pretty good.), fish food, or just sit back and wait, testing daily until u test 0ppm ammonia, 0ppm nitrites, and below 20ppm nitrates(if u want ornamental invertabrates, u would want below 5ppm nitrates.)for any way u cycled the tank-than u r ready for some hardy fish. u might be amazed by the pomacantus and holacantus angels and butterflyfish, but hardy fish can be just as magnificent! blue devil damsels r a striking electric blue, and males often develop yellow to red fins when they mature, clownfish(specifically the species Amphriprion ocellaris) have a comical white-striped orange pattern, centropyge angels r extremely colorful and one of the most hardiest type of angels, though on a difficulty rating of 1* to 5* they would probably a 2.5* rather than the 1* clownfish and blue devil damsels r. hope this helps!