SeaView Mounting and Illumination Solution for Aquarium Background seals your background to your aquarium, eliminating ripples, bubbles, and the refraction of light behind the glass resulting in a flawless, illuminated, 3D view of your background from every angle. This solution is easy to apply and removable for convenient background changes. It is completely non toxic and can be used with freshwater or saltwater aquariums, whether glass or acrylic. 1-ounce gel treats up to a 75-gallon aquarium.