An alternative to siliconing it permanently inside the tank would be to buy the largest magnets home depot or lowes has and silicone them onto the back of the background and place the other magnets on the outside of the tank. It worked for me on a 7ft tank. I cut it into two sections and used 9 magnets on the back of each piece. Which would be a total of 36 magnets inclded the ones placed on the outside of the tank. The magnets on the outside dont need silicone. They cost like 1-2 bucks for a pack of 2. Hope that helps
