How to Seal Hexagonal Aquarium Walls

A hexagonal aquarium has a hexagon for the bottom with eight vertical sides. There is a seam between each side. The more seams you have, the more of a chance of leaks due to failure of the sealant. If you seem to be adding water more frequently to keep it at the correct level, you may have a leak. Leaks most commonly occur on the vertical seams of an aquarium, but may also be at the bottom under the black plastic trim. Removing the trim will expose all of the leaks at the bottom, so you can find and repair them.

Things You'll Need

  • Containers
  • Water pump
  • Newspaper
  • Towels
  • Rubber mallet
  • Pliers
  • Grease marker
  • Paper towels
  • Vinegar
  • Razor knife
  • Aquarium-safe clear silicone sealant
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Instructions

    • 1

      Remove your fish from the aquarium and place them in a container or a backup aquarium. Pump or drain the water out of the fish tank. Remove all of the tank decorations, filtration system and the gravel and place it in a container.

    • 2

      Place newspaper on a flat surface such as a table or countertop. Dry the aquarium thoroughly both inside and outside with towels. Place the fish tank on top of the newspaper.

    • 3

      Strike the black plastic trim at the bottom with a rubber mallet using medium force. This action loosens the sealant. Pull all eight pieces of the black trim off with pliers. The bottom seam that connects the bottom section of each vertical side is now visible.

    • 4

      Fill the aquarium slowly with water while observing the newspaper for leaks. When you see an area leaking, mark it with a grease pen on the glass. Drain the aquarium and dry it thoroughly with paper towels.

    • 5

      Cut away the old sealant with a razor knife in the areas that are leaking. Pour a small amount of vinegar on a paper towel and thoroughly clean both the inside and outside of the leaking areas.

    • 6

      Squirt aquarium-safe clear silicone sealant on each leaking area on the inside and outside of the glass. Wet a forefinger and smooth the sealant into the seams.

    • 7

      Allow the sealant to dry completely according to the package directions. Generally, this is about 48 hours.

    • 8

      Fill the repaired fish tank with water and observe it for leaks. Apply sealant to all eight sides on the bottom and press the black trim in place. Replace the gravel, decorations, filters and fish.