I use the Hikari Algae Wafers, but I only have a few small bottom feeders, so I never put a whole one in. If I had a big pleco or something, I would, but the fish I have could never finish one of those fat algae wafers, they are big. I usually brake off a few small pieces, just enough so that it all gets eaten within an hour or so. Maybe your problem is that it not getting all eaten?
Also, the Hikari Wafers (not algae wafers) are much smaller.