I've got these steps and this year I drilled holes in the sides. Three, 3 inch holes on each side.
http://www.lumi-o.com/pro/mod.php?lang=en&mn=5302
After drilling the holes the difference was very noticeable we have yet to see algae in them. Even while we were using Pristine Blue earlier this year we never saw algae in them. We angle our return to the side so it moves the water in a circle around the pool. If the algae is inside the stairs, like mine was, tbit his will definitely help. Now, having switched to BBB all I get in the stairs is a little of a brown residue that the filter won't catch. I just put my vacuum hose in there and it sucks it out.