Has anyone heard of using Mr. Clean Magic Erasers as algae scrubbing pads. I used some today on the tanks at work because another store said they worked and the customers said the tanks looked awesome. I don't think there is anything to them except for a sponge with micropores. So they can't release anything into the water, I don't think. They made the tanks in the systems look great. I used one on the inside of the tanks and another one to wipe the outside and I could tell they did a great job. I mean, it cleaned off algae that the other stuff missed and I didn't even see with my eyes. Then, I got to thinking that if these things are great for cleaning the sides of the aquarium and don't dissolve in the water, (they just get crumpled up) then maybe if I cut them into 1" x 1" x 1" cubes, then I could have myself some very inexpensive biofilter media for the pond filter I am building. Any input? The only problem I can forsee is that a hungry fish would take a nibble out of the side of the pad but I haven't had problems with them yet and I cleaned Oscar tanks today.