(2) Stainless Steel Replacement Blades (Glass Aquariums Only) Algae Free Float Plus Cleaners This is a 2-pack of Stainless Steel Replacement (Glass Aquariums Only) blades for Algae Free Float Plus Cleaners. *Blades are made of high quality 316 stainless steel which is highly corrosion resistant but we still suggest removing from the aquarium when not in use. To replace the blade: 1. Remove old blade by grabbing the plastic piece in the center with your thumb and index finger and push down on the blade with thumb. 2. Reverse the process to replace with new blade.