what's with the ammonia reading? it doesn't sound right, you shouldn't be having any reading for ammonia. a couple of other questions:
a. just what kind of corals are you planning to keep? placement of the corals ( ie near the top of the tank or middle or bottom)
b. the light you metioned wouldn't be enought except for some low light kinds like mushrooms
c. nitrate reading is high for corals, you need it to be much lower like zero.