[Nerbil]

How to Reseal Your Glass Aquarium
The aquarium is perhaps the most vital piece of fishkeeping equipment, but larger tanks can be expensive and silicone doesn't last forever. Resealing a leaking tank may sound like a daunting task, but it's a relatively straightforward, simple project that can save you a substantial amount of money. This article applies only to glass tanks with compromised silicone seals; the repair of acrylic tanks or glass tanks with broken or cracked panels is outside its scope.

Supplies

• 100% Silicone sealant (clear or black recommended)
  
• Rubbing alcohol
  
• Masking tape
  
• Single-edged razor blades (available in hobby stores and hardware stores)
  
• Paper towels
  
• Cotton balls, swabs, or pads
  
• Optional:
  
  • Latex Gloves
    
  • Razor blade holder
    
  • Tweezers or needle-nose pliers
    
  • Caulking gun
    
  • Small dish or shotglass
    
  • Mineral spirits
    
  • Scissors and pencil or skewer
    
  • Vacuum cleaner with hose attachment

Although aquarium sealant purchased from a pet or fish store is guaranteed safe, a more cost effective solution is to buy silicone from a home improvement store. It must, however, be 100% silicone, FDA approved for food contact surfaces and it must not contain any additives or fungicides, as these may be toxic to your fish. "GE Silicone I" is a brand known to be aquarium safe. If you are using these tubes, you will need a caulking gun in order to apply a uniform bead of sealant. Aquaria larger than 30 gallons may require multiple tubes of silicone. You will need scissors and a skewer or pencil to cut the tip and break the seal on the tube of silicone.




Preparation

• Work space: Clear an area to place the aquarium that is completely flat. Working on an uneven or incomplete surface risks cracking the tank. The work area should also be well ventilated.
  
  
• Prepare supplies: Have all of the things you'll need at hand; silicone dries faster than you may think.
  
  
• Remove old sealant: Since fresh silicone does not adhere well to cured silicone, you must remove all the sealant from the tank and start anew. Using your razor blades, firmly press against the glass and slowly slide down underneath the silicone until you hit the glass. Repeat this along a length of sealant and then do the same on the opposite side of the sealant line.

Do not remove the top and bottom trim--it is helping to keep the glass in place!

• Clean the seams: Using a cotton ball, swab or pad, clean the areas where the old sealant had been with rubbing alcohol. You can use your finger dipped in alcohol to feel for any rough or tacky spots where silicone still remains.

• Repeat if necessary: If there is still silicone, let the alcohol dry and then use the razor again to remove any residue.
  
  
  Tips:
  • Pour a bit of alcohol into a small dish or shotglass for finger dipping - this will come in handy throughout the project.
    
  • Keep your razors fresh for clean removal - it may take 2-4 blades depending on the size of the tank.
    
  • Be careful with the corner of the blade - you don't want to scratch the glass.
    
  • Its okay to remove a bit of sealant from the space where the glass meets, but don't dig so that you break that seal or pry the glass apart.
    
  • Use tweezers or needle-nose pliers to remove sealant from the corners.
    
  • Use a vacuum to remove the silicone bits and pieces as you go.
    
  • Slow, controlled razor strokes will help keep the sealant in large pieces and prevent chipping and flaking. Sometimes this is inevitable if the sealant has dried out, resulting in the mess below:

Resealing the Tank

• Masking: Using the masking tape, mask the seam areas that will be resealed. There should be faint lines left behind from the old sealant; use these as a guide to determine the width. Use a razor blade to cleanly cut the tape at the corners. It will come in handy to leave "tails" of tape coming up out of the top of the tank - these will make the tape easier to remove later on.

Work in a well ventilated area and do not place your face or head inside the tank while applying silicone!