i used to use a g2 too. my lighting regime was : 130 royal blue ON, 230 not so bright white on, 430, rest of the bright white light on, 1030, bright light off, 1130, not so bright white off, 1230 royal blue off.
this at least gives some sunrise/sunset effect to it.. i only keep the majority of white lights on for 6 hours because i have a very shallow tank and worried corals might bleach.. since yours is a 2ft cube, can consider going longer period if you are keeping sps.