Welcome,
If you succeeded with discus you will have a blast with saltwater.
I started in late October with a 16 gallon SERA biotop I bought on line from PETCO for $169 on sale. It has a great hood. It has a 18 watt CF white/actinic bulb. The PAR measurements are low but probably fine for your objectives. I have it in my office and it is a nice quiet and attractive setup for that situation. B at Unique Aquaria has one across from his sales counter that has a hood modified with LED's. He strongly endorses it but cannot obtain one for you because the distributor doesn't ship small lots. I don't know if PETCO carries the manufactured LED hood that SERA makes. Last year it was only available on the larger model sold in Europe.
I currently have 2 A. ocellaris, a black ray goby and his roomate a candy striped pistol shrimp, a barnacle blenny, and blue legged hermit crabs and various snails.
For filtration I rely primarily on the sand and rocks. I placed some broken rock in one of the back chambers. I recently started alternating with the "cut to fit" phosphate and nitrate filter pads.
I do at least 10% weekly water changes I prefer water changes twice a week when I can. It's a good compensation for a low tech approach.
Also I feed lightly, primarily "Breeder's Hatch" Frozen cyclops also worked. Frozen mysis seem too large for these fish. I occassionally feed the coral, but need to be cautious about the bioload. With light filtration there are some suspended material in te water for the filterfeeders. It is light enough to not distract from the clean look of the tank when viewing.
I bought a small amount of live copepods from B at UA, about 3-4 months ago and placed in the rock rubble chamber. I now see them in the main display area if I move a rock. I believe the shrimp and nerite snails do a great job in maintaining the health of the sand bed.
Successful corals have been my Duncan, zoa's, polys, deveil's hand leather, candy canes, toadstool, slow growth from a mushroom and ricordia, but I may have injured them over time with mounting and maintenance.
Known hitchikers- dwarf black brittle star- good. Apitasia and mujano anemone- bad.
Losses- 2 trimma gobies, 1 peppermint shrimp, 1 hector goby. I don't know if these were lost due to weekend feeding schedule. After losing the hector goby I bought an auto feeder. The trimma's are very shy so it is hard to know when they died, but they no longer appear. Maybe the black brittle star wasn't that good.
Here are some pictures and a brief video of my black ray and barnacle blenny feeding.
Featured presentation-
[video]http://s29.photobucket.com/user/FishportNH/media/BlennyontheMove_zps591be39a.mp4.html[/video]
Hope to meet you at one of the fall meetings. I'm looking forward to a future meeting when our club president announces he has finally managed to keep a coral in his tank!
Ralph