Large Windows

I have one tank next to a window that faces west, I wish I had a UV filter because I always have more of an algae problem on the side of the tank by the window, and I keep the curtain closed. There is a bit of light that tends to sneak in and it seems to be enough to cause a problem. I've also read that sunlight is good for tanks, but you have to make sure everything else is in check or you will get an algae problem!