In addition to reducing lighting time and careful feeding, I would also check your water parameters both in the tank and at the tap. The limiting factors for algae are phosphate and nitrate (think fertilizer for a garden or houseplant). If these are present at the tap, water changes will only provide a new food source for algae. If they are not present at the tap, continue water changes and monitor these chemicals on a daily basis to see a drop in them. Also, look for anything decaying, maybe a dead fish or snail. Most fish foods use phosphates as a preservative so limiting feeding may also help. If the chemicals are present at the tap, a deionizing filter or reverse osmosis filter will help. No need to spend this money if not needed though.
Charlie