4-inch by 6-inch white pad
White is acrylic tank surfaces
Also available in two convenient sizes: 3-inchx 3-inch and 4-inch by 6-inch blue for glass aquariums and white for acrylic
Surface friendly Algae Scrub Pads are safe, non-toxic and easy to use for removing line scum, unsightly algae and other deposits that form on aquarium surface.
Lifegard Aquatics 4-Inch by 6-Inch White Algae Pad - B000256688