biOrb cleaning pads are the safest and most effective way to remove algae from your biOrb aquarium without scratching its acrylic surface. Available in packs of 3, the special cloths have a smooth side for regular cleaning and a rough side for tougher algae marks. The rough side of the cloth can also be used to remove limescale from the base of the light unit. These pads should only be used on the inside of the aquarium. It is recommended that only official biOrb cleaning pads be used, as other brands may scratch the acrylic.