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3 Tempered Glass Aquarium Questions Answered!

If you are getting into the hobby of aquariums and keeping fish, you might be starting to research the different kinds of glass available and which tank is generally considered the best option for your needs – or even how to make your own.

In this case, you may have come across the phrase “tempered glass aquarium” and wondered what this refers to.

With any hobby, it’s important to do thorough research into the different terms and the items available, particularly for your early purchases, where you will have little background knowledge to work with.

Tempered glass has many useful applications in everyday life, and some items depend upon tempered glass to work well – it is shock-resistant and tougher than normal glass, so it will stand up to more pressure and weight.

This makes it suitable in particular situations, but you don’t always want tempered glass as it has some disadvantages.

Do not build your own aquarium with tempered glass – or at all – without a good understanding of what you are doing, as mistakes could be expensive and extremely damaging to both your fish and your home.

If you are looking to purchase an aquarium, you may see some sold as tempered glass aquariums and some sold as normal glass, which could leave you wondering which is better and why. There are pros and cons to both, which we will explore next.

What Is Tempered Aquarium Glass?

There is no such thing as specific tempered aquarium glass, but tempered glass is sometimes used in aquariums because it can bear more weight than standard glass; it is created in a different way, which increases the overall strength of the sheet.

When tempered glass is made, it is heated intensely, and then cooled down swiftly. This process changes the structure of the glass and gives it some unique properties, including extra strength, but creates tension across the whole sheet.

The piece of glass at the bottom of your aquarium needs to be strong, because it has a lot of weight on it thanks to the water, the substrate, and the tank contents.

If normal glass is used, it must be thick in order to bear this weight and maintain the structural integrity of the tank. However, thick glass has high manufacturing costs and will add to the weight of the tank, making it more expensive to ship.

Tempered glass helps manufacturers to save on freight costs because it allows them to use much thinner (and therefore lighter) glass.

Although tempered glass can be more expensive because it has to undergo this specific treatment, the savings on thickness and shipping fees often outweigh this cost.

Is Tempered Glass Good For Aquariums?

There is some debate as to whether tempered glass is suitable for aquariums, but many dedicated hobbyists recommend against its use if you are going to be building your own tank.

Despite the extra strength it offers, a tank that incorporates tempered glass will still be weaker and more prone to breakage than one that uses a sheet of normal glass at the correct thickness.

If tempered glass is going to be used, it should only be used for the base of the tank, because it comes with some major issues; most importantly, it is vulnerable to scratches and will break more easily than normal glass, which could result in your tank shattering all over the floor.

Although it does have better impact resistance and is scratch resistant, if it is damaged, it is more likely to break.

Tempered glass also often has some distortion as a result of the glass being pulled in sharply when it cools; different parts of the glass contract at different rates, which results in some minor defects and areas of distortion.

This is an issue if you wish to use sheets of tempered glass on the sides of the aquarium, because they will not provide you with a perfect view of your tank – and most hobbyists want their display to be as crystal clear as possible.

This distortion is usually very minor, but it can still be annoying.

Are All Glass Aquariums Tempered Glass?

Not all glass aquariums use tempered glass on the bases, but it can be challenging to tell whether yours does or doesn’t, especially if you have got it second-hand and you don’t know what brand it is.

This can be frustrating if you want to modify your aquarium, as tempered glass will shatter if you try to drill it, whereas normal glass will not.

The best way to tell whether an aquarium has a tempered glass base is to contact the manufacturers and ask, as you will be unlikely to know for sure just from looking at the glass – although sometimes, tempered glass does have a stamp carved into it.

If you cannot contact the manufacturer, you may be able to tell by looking for the distortion, which is particularly obvious if you wear polarized sunglasses; these will pick up on the rainbow refraction.

A more drastic test involves trying to scratch the glass. Normal glass will scratch easily, and the sheet should remain intact, whereas tempered glass will not scratch easily, but will shatter if you do scratch its surface.

This test should only be undertaken if you must find out what kind of glass has been used and you have no other options, as scratching the glass of your aquarium is an undesirable thing to do (and should be done in a hidden corner if at all).


A tempered glass aquarium will enjoy the benefits of a thinner base and consequently lighter overall tank, and this is common among commercial aquariums because it reduces costs for the manufacturers. However, many hobbyists prefer to build tanks with thick bases to increase the strength and integrity of the aquarium and reduce the risk of any small scratch destroying the entire tank. If you are building your own tank and you wish to use tempered glass, make sure that you only do this for the base, as it isn’t suitable for the tank sides.