Is Tempered Glass Better for Aquariums?

Aquarium manufacturers offer selected tank sizes constructed of tempered glass, as opposed to standard plate glass construction. Tempered glass is made by heating ordinary glass red hot, and then "quenching" or quickly cooling it with jets of cold air. As with any aquarium technology, tempered glass provides both advantages and disadvantages. Important considerations are strength, weight, safety and tank size.

Strength

Tempered glass is at least four to five times stronger than plate glass. This means that, for a given size tank, the glass used can be thinner if it is tempered. Most glass tanks have tempered glass for the bottom. Greater strength means the glass is less easily broken.

Weight

Because using tempered glass allows the aquarium to be made of thinner material, a tempered glass tank weighs less than the same size tank constructed of standard glass.

Safety

Besides being stronger than standard glass, and thus less likely to break, tempered glass offers an additional margin of safety--when it does break, tempered glass shatters into small, rounded pieces, rather than producing sharp fragments.

Tank Size

Tempered glass always has slight warps or ripples, and the edges are seldom perfectly straight. This fact limits its usefulness in constructing large aquarium tanks, because of the gaps created where two pieces meet. The gaps must be filled with silicone sealer, reducing the overall strength of the seam.

Warning

Tempered glass cannot be cut or drilled successfully. All shaping must be done prior to the tempering process. Do-it-yourself projects are therefore limited to the size and shape of tempered glass available. For this reason, it is more cost effective to have custom sizes or shapes of tanks built by a factory.