How to Tell If Your Tank Is Tempered Glass or Not

Tempered glass has been heated to extremely hot temperatures and then quickly cooled to toughen the material. Most aquariums are made with tempered glass to withstand the weight of the water in the tank. Tempered glass can also be found in car windows and computer monitors. In most cases, a stamp is placed on the tank to identify the material as tempered glass. Tempered glass may also exhibit imperfections due to the heating process.

Things You'll Need

  • Polarized sunglasses
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Instructions

    • 1

      Look at the corners of your fish tank. Find a stamp identifying the manufacturer and its registered trademark. Read the code underneath the manufacturer's trademark. The code refers to the type of tempered glass. L stands for laminated, which means a laminate has been placed on the tempered glass, such as tint or window film. T stands for toughened, meaning it was heated and rapidly cooled to make it stronger. The rest of the code shows the graded results of the impact testing performed by the manufacturer. Weight is applied to the glass to determine how much pressure it can withstand. Grade A can withstand the more pressure and weight than grade B or C. The remainder of the code refers to the manufacturer's standardized test number.

    • 2

      View the tank from an angle. Stand to the side of the tank and look across the front of the glass. Imperfections may occur on tempered glass due to the heating and cooling process. Glass is removed from heat using tongs, which may indent the the glass when it is still hot. Look for waves or bumps.

    • 3

      Stand to the side of the tank and look into the side. Place your hand near the glass at the front of the tank. You should not be able to see your hand. When tempered glass is heated, tiny stress fractures are produced on the outside of the glass. The inside of the glass remains intact. This creates a reflection when viewing the tank from an angle.

    • 4

      Put on pair of polarized sunglasses. Stand to the side of the tank and look across the front of the tempered glass tank. Look for black lines that occur during the heating and cooling procedure. Polarized lenses reduce reflected light and remove the glare from view.