Hi bros and sis here,

I recently bought a 3D background made of styrofoam. I wish to install this 3 inches away from the back of my tank.

Due to the natural buoyancy of this material, is it enough to just silicone the sides and bottom of my background?

Are there any techniques or any other suggestions as to how i can achieve this?

(The background is about 3 inches thick, and i want to install it into my 1ft cube tank. So the background i am going to cut out will be 11.8'' x 11.8'' - Measurements if you need it to calculate anything??)