How to Replace the Silicone Seal in an Aquarium

Glass aquariums are made out of four glass panels that make up the sides and one additional glass panel on the bottom. All of the glass panels are joined together and sealed with silicone caulking to keep the water within the tank. If the silicone fails over time, a leak will occur and you must replace the old caulking to preserve the integrity of the aquarium. A leaking tank can be fixed by any do-it-yourselfer with a few supplies.

Things You'll Need

  • Work gloves
  • Straight-edge razor blades
  • Fish tank silicone caulking
  • Fine grit glass sandpaper
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Instructions

    • 1

      Prepare the tank for repair. If the tank has live marine life within, confer with your local fish or animal store as to the proper care for your fish while they are outside of the aquarium. Remove the fish according to the instructions of a qualified professional. Drain the aquarium of all water and allow the interior to completely dry before removing the old silicone caulking.

    • 2

      Remove all of the old caulking from the glass panes. You can choose to completely disassemble the aquarium, or you can remove the caulking while the tank is still intact. Use the straight razor blade to cut the caulking away from the glass. Apply pressure against the surface of the glass and slide the blade under the edge of the caulking.

    • 3

      Sand the surface of the glass to completely remove any of the old caulking, which will prevent the new caulking from bonding. Completely clean the surface of the glass to remove all dust and residue with water and a sponge or towel and allow the surface to dry.

    • 4

      Apply a bead of caulking where two glass panes meet. Work on one joint at a time and immediately run your finger over the bead to smooth the inside edges into a smooth surface. Wipe away the excess silicone on a towel or sponge and repeat the process for all inside corners. Allow at least 48 hours for the silicone to dry before adding water.