I feed one large pinch of dried brine shrimp once a day, one large mats of purple veggie twice a week, and a lot of frozen brine, mysis, cyclo, reef roids, phyto and bloodworms once every 3 days or so, that are rinsed thoroughly and plentiful, and silverside by hand to the lobster, all with the pumps off. I maintain low nitrate and undetectable phosphates, and over-skim. I'd say I grossly underfeed.
But the fish are fat, happy, and visibly healthy.
Though now after reading everyone's comments, I'm considering feeding more, daily.