Use the search button for silicone because aquarium safe silicone is available in every hardware store. Also, I'm not sure about the LFS in your area but when I'm missing something or I have a broken piece of replaceable part, I go to my LFS and a lot of times either they have the part for sale or they have an extra piece to give me for free. I'm not talking about chain pet stores (Petco, Petsmart...) but owner owned stores. Check it out. The Doctor.