i have a koralia 1 and a rio800 with the spinning attachment, a 250w 14k MH(bulb is only a couple months old), no skimmer, 2 hang on back filters, i feed once a day and they eat it all. i have a maroon clow, fang goby, domino damsel, and a scooter blenny. tank has been up for about 5 months or so with no problems up until recently.