Once or twice a week is good. SushiGirl has a wonderful tank with lots of softies and LPS so she needs to feed frequently, and she also has excellent husbandry skills to handle the high nutrient load. Yes, twice a day is too much for what you have. Coral will eat what they will eat, and the rest becomes dirt which eventually feeds algae.
Asumming your lighting is sufficient, a good feeding once every 2 weeks should be fine IMO. Let's hope that everything your feeding now is being consumed, but you are walking a tight rope between a tank that has a nutrient problem, and one that does not.