Mag-Float Nano Glass Cleaner (Curved) Recommended for use with glass aquariums up to 30 gallons with a surface thickness up to 3/16. Product dimensions: (diameter: 2.5, height: 1) Contain special abrasive velcro pads that remove algae from the surface of your aquarium. The Mag-Float floats when the inner magnet separates from the outer magnet. Magnet does not lose strength over time