There are quite a few differences between acrylic and glass aquariums.
Glass is a long-time favorite of many aquarists because it is traditional and therefore has a loyal following. Aquarists who favor glass believe acrylic is a poor choice because it scratches easier than glass. Although this is true, the material has many advantages over glass.
For one, acrylic is 17 times stronger than glass, softer and more flexible than glass, making it highly impact resistant.
Secondly, it weighs 50% less than glass, making it much more portable.
Thirdly, acrylic insulates 20% better than glass, which reduces temperature fluctuations and saves on heating and chiller bills.
If these benefits aren't enough, the seams of these tanks are molecularly welded. The resin used to seal them chemically melts the two pieces of material into one solid piece for a clear polished seam that is virtually unable to leak.
Another advantage is that it has a transparency rating of 93%, which is as clear as optical glass. In fact, acrylic passes the most light of any known material.
For all of these reasons virtually all modern public aquariums are made from acrylic. And while the material can scratch, scratches are easily buffed out without having to remove fish or water.
Many myths have been laid to rest about acrylic. Some believed it could turn brittle or yellow with time. Plastic can do this, but acrylic does not. Others believe these tanks bow and distort. An tank made of this material to proper specifications will not bow or distort. One caveat that my be important to know, however, is that it is flammable. You won't want to create ambiance by setting a burning candle on top of your tank.
The best type of acrylic for an aquarium is domestic cell cast. Polycast is an excellent brand, but other brands will also make an outstanding aquarium. Rohm and Haas, Cyro Acrylite, and Lucite are just a few.
When searching for an acrylic tank, the top which has cutouts for filters and access should be the same thickness as the walls and bottom. Also note that these aquariums need stands that support the entire bottom of the tank to distribute the weight evenly.
More aquarists every day are turning to acrylic because of its many advantages. If you are switching from a glass tank, remember to use acrylic tools to clean the walls of the tank, never a razor. You can purchase large plastic blades for this purpose.
Glass tanks have played a historical role in fishkeeping, and will continue to provide pleasure for those who remain loyal. But in an objective review of the facts there is no doubt that acrylic tanks are the wave of the present and the wave of the future.