I look at it like this, to get rid of the algae you have to find out what's causing the algae, which can be a few things:
1) Too much light
2) Phosphate and nitrAtes are too high
3) Sunlight
The first thing I'd do to cut down on the green algae is to get a nitrate and phosphate test, preferably the liquid tests. Weekly water changes, anywhere between 15% and 30% will keep the nitrates and phosphates down. But if the nitrate and phosphate test results are high I'd do a 40% water change first and maybe 10% - 15% water change every couple of days until the nitrates and phosphates come down. I wouldn't do a lot of huge water changes back to back so it won't shock the fish.
Personal experience
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Before I started doing any water changes, I was just topping of the water for about a year, any new fish I added to my aquarium would be dead in two days. The fish that were already in the tank lived on though. Also I had to clean my aquarium glass at least once a week or else it'd be green. I had already given up on the decorations inside because they were covered in algae, pretty much looked like grass. I took a water sample to the local fish store and they said that my fish were pretty much swimming in turpentine. The phosphate test was so far off the chart that the tested water was black. The last level on the chart was a dark blue.
So they had me do the big 40% water change then 10% each day after that until the levels had gone back down. Although I do use a phosphate remover in my tank now, the levels are under control and I do not have any green algae in the tank. It's acceptable to have a little algae, but I don't have any in the tank now.
.02
