IMHO going dark will slow the problem down but not eliminate it, you need to deal with the nutrients feeding the problem, check your tds, add a phosban reactor and or cheato to your refuge section and water changes, light does not fuel the problem nutrients do, our 55g gets lots of direct sunlight and 12 hours of T5 lighting and we have little algae growth besides coralline, increase your flow, and set your skimmer to skim wet will help also, just my 2 cents