How to Drill a Fishtank

Reef aquariums require a constant flow of water to keep the system in balance. While this can be achieved by pumps and filtration systems that attach directly to the aquarium, many people prefer to use an external sump. A sump pumps water in and out of the aquarium through hoses that go though holes that are drilled in the side or the back of the aquarium. The sump can be kept out of sight so that it does not distract from the beauty of the aquarium. Many aquarium shops will drill these holes for you, but you can save money by drilling them yourself.

Things You'll Need

  • Electric drill
  • Diamond-tipped hole-cutting bit
  • Guide plate
  • Spray bottle
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Instructions

    • 1

      Lie the aquarium on its side if possible so that the surface you will be drilling is horizontal. If you are drilling into an aquarium that is already set up and you do not wish to empty it, lower the water level below the point where you will drill the hole.

    • 2

      Place the guide plate against the glass so that the hole in the guide plate is in the correct spot. Most hole-cutting drill bits come with a guide plate, or you can buy one separately.

    • 3

      Squirt the glass with water and then fit the hole-cutting drill bit into the guide plate. Put the drill on its slowest setting and begin grinding the bit against the glass. Maintain a low, steady pressure. Let the bit do the work, and do not try to push down on the drill to speed things up. Remove the guide plate once you have a good start on the hole.

    • 4

      Create a "dam" around the hole using modeling clay if you are drilling on a horizontal surface. Make the dam about 1/2-inch high and then fill it with water. The water will lubricate the drill bit and keep it cool, reducing the chance of splintering or cracking the glass. It will also extend the life of the drill bit.

    • 5

      Continue spraying the glass with water if you are drilling a vertical surface. Make sure the drill bit stays wet. Lift the bit slightly about once a minute to make sure the water flows to the bottom of the cut and adequately lubricates the tip of the bit.

    • 6

      Slow the drill down if possible once you are close to breaking through the glass. The chances of the glass splintering are greatest when the bit breaks through. Have someone hold a wet paper towel on the other side of the glass to prevent the glass plug from falling and to keep the water from flowing out of the drill hole. Make sure the person's hands are clear of where the bit will punch through the glass.