How To:

Resealing an Aquarium

I often get the asked about resealing leaking glass aquariums. 

I don’t do this anymore mainly because my insurance company would have a cow, but I have done it in the past.  If you own a maintenance business, DO NOT reseal a tank and place it in a customer’s home or business.  You don’t want to have to replace a floor if it starts leaking again.

If it’s your personal aquarium and you feel like this is something that you want to tackle, here are a few things to consider.

  • If you have a glass tank that is leaking, you HAVE to remove all of the old silicone to repair the leak.  New silicone will not bond to old silicone.  It will eventually start leaking again.
  • Use a razor blade to remove ALL of the old silicone from the edges and corners.  There should be nothing visible at all.  You do not have to take apart the glass panels unless one is cracked.
  • Clean all of the edges and corners thoroughly with rubbing alcohol.
  • For a neat resealing job, use painter’s tape to go along each edge leaving approximately ¼” from the edge for silicone.  Use a razor blade to trim and tidy up corners.
  • Use 100% silicone without bacterial inhibitors.  There are ones marketed just for aquarium repair.
  • Apply silicone sparingly into the edges and corners.  Wet the end of your finger with a wet paper towel and run your finger along the bead of silicone, pressing it into the edge and along the tape.  The silicone should taper down to almost nothing as it touches the tape. Wipe excess silicone from your finger onto another paper towel.
  • Once you are done smoothing out the silicone, VERY CAREFULLY remove the painter’s tape.  If the tape pulls up some of the silicone, DO NOT try to smooth it back out.  Let it dry thoroughly then trim it with a razor blade.  If any other silicone touches the glass, wait and remove them with the razor blade when they are dry.
  • Let the tank dry for at least 24 hours before filling with water.  Watch for leaks as you fill.

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