4 hours of lights on followed by 4 hours off, followed by 4 hours on...
I have mine on from 7am-11am, then off from 11am-3pm, then on from 3pm until about 7pm, sometimes I keep them on a little longer. Then they are off until 7am and the cycle continues.
I split bulbs as well...From 7am-9am it's only 2 bulbs(54wx2), then it goes to 4 from 9am-11am. Then I use all 4 from 3pm-5pm, then cut to 2 from 5pm-7pm.
Fish and plants don't seem to mind and the cyano hasn't shown up since. For some reason, my RTS seems to be out in the open more since I changed schedules, but that could just be coincidence.