Mexican Turbos or a sea hare. I'd try one of these and look at limiting your nutrient inputs. Look at how much you are feeding. Are you using filter socks or any type prefilter media, If yes, how often do you clean or change it out?
If you have a lot of horizontal surfaces in the tank, blowing them off once a week can help a lot as well. Detritus can settle on flat surfaces and crevices as. Algaefix works, but I'd try limiting inputs and some algae eaters before I use it.