Acrylic vs Glass Tanks: Pros and Cons

Acrylic vs Glass Tanks: Pros and Cons

An aquarium is a special enclosure or well-designed structure used to confine and display aquatic organisms, i.e. live plants and animals such as fish, invertebrates, amphibians, and reptiles.

The two main materials for making aquariums are acrylic (plexiglass) and glass. These materials have varying characteristics (weight, insulation, durability, etc.), pros and cons, and also their prices differ significantly.

In this article, I will highlight the features of both aquariums with their pros and cons to enable intending aquarists to make informed choices.

Glass Aquariums

The first modern aquarium was made of glass and it was developed in the 19th century by Sir Robert Warrington.

Note: During this period, aquariums featured slate or steel bottoms, alongside glass paneling attached with metal frames and sealed with putty. This allowed the aquarium to be heated with an open flame heat source beneath; thus providing warmth for the aquarium inhabitants. Up until the mid-1960s, metal-framed aquariums were prevalent; later on, these were phased out and replaced by silicone-sealed styles.

Nowadays, a large percentage of aquariums are made from glass panels. These are bonded and held together using a 100% aquarium silicone sealant.

Also, a common feature in most present-day glass aquariums is the addition of tempered glass at the bottom. This confers strength to the aquarium by boosting its impact resistance, however, the rest of the panels are made with plate glass.

A glass aquarium is an enclosure made of glass and it can be crafted for sizes up to 1,000 liters or 260 gallons. Glass tanks are mostly made in rectangular/cuboidal shapes, whereas fish bowls are typically spherical.

It is worthy to note that irrespective of its popularity, glass can be brittle and just a little impact can cause fracturing of the panes. And the bonding material used to join the glass panes at the seams may weaken over time, resulting in a leak.

Glass aquariums have enjoyed fame for the longest time and it has always been a popular choice for many home aquarists. A notable aspect of glass aquariums is the use of silicone sealant which provides a good long-lasting, water-tight seal around the seams. And this water-tight seal has since eliminated the need for structural frames.

Also, glass aquariums provide less temperature insulation making it slightly difficult to maintain the temperature at a particular set point. What’s more? The cost involved in producing glass aquariums is lesser and they are generally more resistant to scratches.

Pros of Glass Aquariums

  • Cost: Glass aquariums are generally less expensive than acrylic aquariums. However, when constructing very large aquariums using sheets of glass, it can cost as much as acrylic ones.
  • Less Prone to Scratches: In contrast to acrylic aquariums, glass aquariums offer more resistance to scratches and scuffs.
  • Durability. Glass aquariums are sturdy.
  • Chemical resistant. Resists absorption of chemicals.
  • Availability. Glass aquariums are by far the most available on the market.

Cons of Glass Aquariums

  • Weight. Glass is denser and heavier than acrylic. This may not be a problem when it comes to smaller glass aquariums, but for large ones, it’s a different story.
  • Fragile. Glass aquariums breaks or chips easily due to the fragile and brittle nature of glass. This is very likely to occur when a heavy item or high-impact force is applied to the tank.
  • Hardly modifiable. Not ideal for drilling. Even with proper tools, there is a big chance to chip the glass.
  • Forms. They have limited designs and shapes; mostly cuboidal or rectangular because glass is very rigid, brittle, and difficult to shape.
  • Can’t be polished. If you manage to scratch the glass, scratches cannot be easily buffed out from glass surfaces.
  • Seam problem. The seams in glass aquariums are potential weak points. Silicone sealant is applied at the seams in order to hold the glass panes together and maintain structural integrity. This sealant may become weak, damaged, or loose over time, and that can engender leakage of aquarium water. Generally, problems start after 7-10 years.
  • No temperature insulation. Glass tanks do very little to insulate against heat loss.

Acrylic Aquariums

Acrylic aquariums gained popularity and were exposed to the general public in the 1970s.

These are made from acrylic or plexiglass; a transparent thermoplastic often used in sheet form as a lightweight or shatter-resistance alternative to glass.

In recent times, acrylic aquariums have keenly competed with glass aquariums because of the distinctive features and benefits that emanate from them.

As I mentioned before, this type of aquariums is crafted from transparent thermoplastic known as acrylic, acrylic glass, or plexiglass. The acrylic panels are not glued, rather they are bonded. This is made possible by an acrylic soluble cement that softens the plastic surfaces and allows them to merge. The materials are thereby connected and structured into one piece.

Unlike glass aquariums, the view of the acrylic aquarium display remains as clear and transparent irrespective of the thickness of the acrylic material.

Several shapes can be achieved when using acrylic to make aquariums such as U-shape, heart-shape, hexagonal, octagonal, cylindrical and cuboidal shapes because it is easily drilled and manipulated.

Furthermore, acrylic aquariums tend to discolor over time — following long-term exposure to UV light, and it equally becomes brittle.

In addition, acrylic is said to be stronger than glass and it does not weigh as much as the latter. It also provides a certain degree of temperature insulation and this is beneficial to the aquarium critters.

Using an acrylic aquarium makes it easier to achieve tropical temperature especially in very cold climates, thus maintaining a stable water temperature. As a result, you wouldn’t need a very high wattage heater for your tank, and this helps reduce the cost spent on electricity.

When it comes to scratch resistance, glass aquariums come out on top as acrylic aquariums tend to scratch and scrape easily. The good side, however, is that when scratched acrylic aquariums are properly polished — they become as good as new.

Pros of Acrylic Aquariums

  • Less Weight: Aquariums crafted from acrylic are lighter than their glass counterpart.

To confirm this, place a small acrylic aquarium and glass aquarium side by side, lift both and you will notice that the acrylic aquarium weighs less.

Due to this attribute, even large acrylic aquariums are easily moved or transferred from one location to another.

Note: Glass weighs 2.45 g per square centimeter. Acrylic weighs 1.19 g per square centimeter. Basically, at less than half the weight of glass. 

  • Increased Transparency: Acrylic aquariums offer less visual distortion compared to glass, and this allows for a better viewing experience. Also, they don’t give off the blue-green tint seen in some glass aquariums.

Note: The refractive index of clear acrylic is 1.48. Whereas glass has a refractive index of 1.53.

  • Optical quality: Acrylic also transmits up to 92% light compared to 85% of glass.
  • Increased Durability: Acrylic aquariums are way more durable than glass aquariums.

The acrylic material does not shatter easily due to its tensile strength, flexural strength, shock, and impact resistance.

Moreover, acrylic or plexiglass sheets are welded into a single piece. This inherent quality of acrylic makes it less prone to physical damages, unlike the alternative glass which is quite fragile and easily broken on impact.

Note: Acrylic is 10-20 times more resistant than glass.

  • Safety. When acrylic shatters, it shatters in large pieces with blunt edges.
  • Extremely Modifiable: Acrylic can be easily drilled, bent, and cut into various shapes, even the unusual ones. Glass aquariums do not offer this flexibility, so that’s one of the main benefits of acrylic.
  • Easily polished. Scratches on the panes of acrylic aquariums can be eliminated through careful polishing.
  • Temperature insulation. Lastly, temperature insulation in acrylic aquariums is far better when compared to glass aquariums.

Note: It is 5.25 times more thermally efficient than glass.

  • Construction: Acrylic aquariums do not have seams, they are bonded. So, it will last you longer without leaking.

Cons of Acrylic Aquariums

  • Scratches. Acrylic aquariums can scratch easily. Unfortunately, this is one of the major disadvantages of acrylic aquariums. So. I will have to repeat it once again – very easy! For example, if the sand gets caught between glass and algae scraper, it can scratch the glass.

Abrasive materials or objects with jagged or sharp edges like gravel, rocks, blade, etc. can scratch the surface of the acrylic aquarium.

This can however be reduced to some degree by careful handling. Nonetheless, polishing kits can be employed to eliminate or minimize the appearance of these scratches.

  • Cleaning/ netting. Because of the scratches, you will have to buy special materials to clean acrylic glass. In addition, it will have to be extra careful during netting fish, shrimp, etc.
  • Discoloration. May discolor and turn yellow over time due to exposure to UV light, and this muddles the overall clarity.
  • Cost. Acrylic is more expensive than glass. The construction and acquisition of a large acrylic aquarium would require a huge sum of money.
  • Availability.  Acrylic aquariums are not sold in every pet shop compared to glass aquariums.

In Conclusion

Comparison Acrylic aquarium Glass aquarium
Cost ++
Availability + +
Weight +
Shape forms +
Transparency +
Optical quality +
Durability +
Modifiable +
Flexibility +
Temperature insulation +
Scratch resistance +
Safety +
Construction + (bonded) –          (seams)

Putting the pros and cons of both aquariums into perspective, acrylic looks like the better option, but some may argue that glass trumps it, and that’s valid too. If you are a perfectionist or use the tank as a display, acrylic aquariums may cause you a lot of headaches because of the scratches.

Regardless, making a choice between an acrylic or glass aquarium ultimately depends on the construction style or design in mind, purpose, and wherewithal.

While many will be comfortable with picking glass aquariums due to their sturdiness and cost implications, others may lean towards acrylic because of its lightweight, transparency, or other desired features that come with the latter.

So whichever aquarium you choose, make sure it is from a reputable manufacturer, and don’t forget to conduct a leak test before use.

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