I have a scrubber that is a little over two weeks old using a 7 by 7 screen. I have a brown spot the size of a baseball on my screen due to the light concentration. I'm using one 23 watt CFL 2700K on each side of the screen about 5 inches away from the screen. I'm currently running 18 hours on and 6 off. Should I decrease my photo period or move the lights 6 inches from the screen? Any help would be greatly appreciated!