idk if u have solveed the prob or not, but the lighting schedual will DEFFINATLY contribute to the green water, ivee recomended 8 hours at the max to hundreds of people and no problems with ANY algae. but with more then 10 hours you will deffinatly grow algae. also a U.V. steralizer will fix your problem in couple hours by eliminating any free floating algae spores in the water. ALSO, cyno USUALY comes in places where nutriant export is poor by the lack of waterflow in the area its growing. i use the rule of thumb of your pumps should turn your water in your tank atleast 6 times an hour.
hopefully i answered a couple questions =)