I got a mag-float algae cleaner thing with the used tank I bought. However, I think it might have the cleaning pad missing. On one side, there is a thin layer of soft fabric, but on the side that was apparently inside the aquarium, there is what looks and feels like the scratchy part of velcro. Is it supposed to be like this? Or will it scratch the glass? I doubt velcro can scratch glass, but I wasn't sure if it is supposed to have something else on there.