Reseal the deal

How to reseal a

fish tank effectively

A fish tank that isn’t 100 per cent watertight is not fit for its purpose, especially for the occupants. Learn how to reseal a fish tank with UniBond’s straightforward guide.

How to seal a fish tank: Act now!

If you’ve discovered a leak in your fish tank, you need to act fast. Even if it is just a small hole, the pressure of the tank’s water can soon strip away even more sealant, leaving the room outside increasingly wet and the fish inside, well, high and dry.

If you suspect your tank is losing water but don’t have visual confirmation, test the seals by holding a sheet of kitchen roll against them for up to 30 seconds. If any water is getting through, no matter how little, it will show up on the sheet and enable you to locate the source of the leak.

How to reseal a fish tank: Step by step

When you’ve discovered where the leak is coming from, you’re ready to begin resealing your fish tank.

  • Drain. Either drain enough water from the tank so that it is below the area you’re resealing, or, better yet, remove the fish and drain the tank entirely.
  • Remove. Use a razor or a sharp knife to carefully remove the area of compromised sealant.

Alternatively, you can employ UniBond Silicone Sealant Remover to break down the old sealant and make it easier to remove. The UniBond Smoother and Remover Tool is helpful for cutting sealant away without damaging the tank.

  • Clean. Use acetone to clean off any remaining sealant residue to ensure the best possible bond for the new sealant.
  • Seal inside. Apply a bead of sealant on the inside of the tank along the seam where the two panes of glass meet, ensuring there are no gaps or air bubbles.
  • Seal outside. Repeat this process, this time outside the tank on the other side of the seam.
  • Check. After the sealant is entirely cured, slowly refill the tank with water and use another sheet of kitchen roll to check the new seal is watertight.

How to fix an aquarium leak: Choosing the best sealant

One of the most important factors when learning how to seal an aquarium is selecting the best sealant for the job. You need a sealant that is both saltwater and freshwater compatible, has a non-toxic formula so it doesn’t harm the fish and which provides a seal strong enough to hold up against water pressure.

Unibond Trade’s Aquarium Sealant is ideal for small to medium-sized fish tanks, thanks to its special aquarium grade silicone formula that cures quickly, is resistant to sea water and salt mist and can withstand constant immersion. It also provides excellent adhesion on glass, ceramics and glazed surfaces, as well as on anodised aluminium, steel, stainless steel, polyester, polyurethane, fiberglass, making it suitable for many types of fish tank.