Hydra Aquatics Sparkly Sponge – 6 pack – Non-abrasive cleaning sponge – For glass or acrylic – Removes algae even from scratches! – High quality double density material – Cut it to use with tweezers – Removes algae, calcium deposits and water stains Hydra Aquatics’ Sparkly Sponge is a highly durable cleaning sponge suitable for both glass and acrylic. The micro abrasive surface allows maximum algae cleaning with minimal effort, even on scratched surfaces. The chemically inert sponge does not add soaps or detergents to the tank, and the stark white color allows the user to visualize when all the algae has been removed. This 6 pack refill allows for the highest quality at the best price.