Hi all i have a Fluval Osaka 260 which has overtank lighting which is fixed to a bracket secured to the back of the cabinet. My question is this, is there an ideal height for the lights above the water surface? On my last setup, a Rio 180, the luminaire was about 6 inches above the surface, whereas on the Osaka it is more like 12 inches i think. On the back of the cabinet there were two height positions for the brackets, and i put it on the higher position. Obviously i cannot get to the back of the cabinet now, but i have got a way of lowering the lights if needed. Any thoughts?