"aquavitro? pad? is the extremely durable algae pad for both glass and
acrylic aquariums. Made from a durable synthetic cross-linked fiber, it has an
extended life that outlasts most competing products. Its size and thickness
allows you to easily remove tenacious algae from the broad sides of the
aquarium, corners, and even from scratches. Finally, its white color makes it
easy to see what you want to remove and when you?ve effectively removed it."