First, you need to let the tank cycle completely. Then, since you are using the Ecosystem filter, I'd add some inverts...snails, hermits, maybe an emerald crab, ect... Then I'd start with a few hardy corals such as zooanthids, yellow polyps, maybe a green finger leather or a colt. Mushrooms would probably do well too. If you are patient enough to let the system go like this for a while, 6 weeks or so, until the Ecosystem filter matures before you add fish, I think you'll have a fairly stable system. You should be able to keep all the the most demanding soft corals and you should be OK with some of the
LPS corals...frogspawn, hammer, bubble, ect...
SPS, clams, and anemones are not an option with the lighting you have. Also, be aware that Ecosystem recommends using a skimmer with
SPS corals. If you upgrade your lighting to
MH later, you'll want to add a skimmer before buying any
SPS. Ecosystem also recommends using some sort of phosphate media to control phosphate levels although you may not really need it. I'd probably go with a Phosban reactor if I were going to use anything at all.
JMHO.