Ready-Made Aquariums

Ready-made aquariums enable the saltwater enthusiast to immediately jump into the hobby without going through the process of designing and custom building an aquarium setup.

A ready-made aquarium by  Red Sea

A ready-made aquarium by Red Sea

But there are certain things to look out for before purchasing a ready-made reef tank.  And all of these considerations also apply if you are a commissioning a custom built aquarium.

A saltwater aquarium can be made out of glass or acrylic, and there are several important considerations to be made for each.

Glass Aquariums | Glass Thickness

Glass thickness determines the overall strength of the aquarium.  The larger the aquarium the thicker the glass needs to be.  Typically, 10mm glass is used in aquariums 3′ x 2′ x 2′, 12mm in 4′ x 2′ x 2′ aquariums and 15mm in aquariums 5′ x 2′ x 2′ or larger.  The glass used in sumps need not be as thick, since the sump is not holding as much water or holding as much live rock and sand as the main display.  Two glass sizes down, relative to the main display, is the glass thickness normally used for sumps.


Samples of 10mm and 19mm low-iron aquarium glass

Glass Aquariums | Float Glass Or Tempered?

Tempered glass is about twice as strong as ordinary float glass.  The downside is that tempered glass shatters into tiny pieces should it be compromised, sending a torrent of aquarium water and livestock onto the floor.

Float glass, however, will crack causing a leak, but not shatter, giving the aquarist time to at least transfer his livestock to buckets, plastic tubs, or another aquarium.  For this reason I’ll take float glass over tempered glass for aquariums. Every time!

Glass Iron Content | Low-Iron And Starphire Glass

That greenish tint you see when looking at a piece of glass through its side is the result of the iron and lead content in the glass.  Low-iron glass is clear, with no green tint, which means greater clarity.  Starphire glass, an expensive low-iron glass, appears light blue when viewed from the side.

Starphire glass is used on very high quality aquariums for the ultimate in clarity but because of its high cost, it is usually used only on the front viewing panel of the aquarium.   But it should be noted that Starphire glass is not as hard as ordinary glass and therefore scratches more easily.

Silicone Quality

Glass aquariums should be held together with high quality aquarium silicone, that is, silicone that is intended for building aquariums.  This is an extremely important consideration.  Some silicone is meant to be used only for waterproofing or insulation.

Silicone quality will determine whether a glass aquarium will leak anytime in its future.   For this reason purchase a reputable brand that comes with a warranty if you’re buying a ready-made aquarium.

Aquarium silicone is available in clear or black, although clear silicone seems to be the standard for most ready-made aquariums.

The Truth About Acrylic Aquariums

Acrylic aquariums are definitely clearer than glass aquariums — clearer even than aquariums built with Starphire glass.  Their crystal clear clarity (when new) is what prompts many to purchase an acrylic aquarium.  Acrylic aquariums are also extremely durable and are not likely to leak or crack even when molded into an unusual shape, like the semi-circular acrylic aquarium pictured.  The slightly flexible nature of acrylic, compared to the rigidity of glass, also makes it a good choice if you happen to live in an earthquake prone area!

But acrylic aquariums have a serious downside.


Semi-circular acrylic aquarium

Acrylic aquariums scratch easily during routine maintenance, such as when removing algae buildup from the viewing panels.  Even a couple of grains of fine sand caught between a cleaning magnet and the acrylic pane can cause serious scratches.

Special non-scratch cleaning pads are available for acrylic tanks, but they are virtually useless against heavy build-up of coralline algae.  No removing algae from acrylic tanks with metal scrapers or razor blades please!

A scratched-up acrylic tank can be polished with a buffing compound to look like new, but it would require emptying the tank completely of water and livestock.   A good option only if you’re putting your acrylic tank up for sale!

An acrylic aquarium requires dilligent, daily cleaning so as to avoid stubborn buildup of algae which will be impossible to remove without scratching the acrylic panels.

Converting A Freshwater Tank Into A Saltwater Aquarium

Should you use a freshwater tank as a saltwater aquarium?

Many saltwater aquarium hobbyists start out first with a freshwater aquarium which they later convert to saltwater.  To keep costs low, most beginners purchase a new tank meant for freshwater, and use it as their first saltwater aquarium.

There are a a few reasons why freshwater tanks should be avoided for saltwater aquarium use.

  • Freshwater tanks have thin glass walls (typically anything between 6 to 8mm), even for the larger tanks.  Saltwater itself is heavier and denser than freshwater.  Add several pounds of sand for a sandbed and tens of pounds of live rock for biological filtration and you have a total content weight that will put extreme strain on all but the most well-built of freshwater tanks.   The make or break clincher would be adding a hang-on back protein skimmer, which will get really heavy when operating and filled with saltwater.
  • Freshwater tanks will have to be drilled for an overflow if you want to incorporate a sump into your setup.  The temptation would be to use a siphon overflow instead of drilling the tank, which I do not recommend, no matter how safe people who use them claim them to be.  Read more about Drilled Vs Siphon Overflows.
  • Modern, commercially available freshwater aquariums come with aquarium stands made out of chipboard covered in a thin formica or vinyl waterproof covering.  Chipboard sags and warps under the extreme weight of a saltwater aquarium over time.  It also absorbs saltwater from its exposed surfaces, usually at the back — the ‘unseen’ part of the aquarium stand — softening and weakening the structure over time.  All of the best ready-made reef tanks come with solid oak or pine wood frame stands.  Marine grade plywood is also a viable alternative if the aquarium stand is well constructed.

Unless you are setting up a nano aquarium of 15 gallons or less, avoid tanks designed for freshwater aquaria.

Sump Or No Sump?

There are many advantages to having a sump as part of your aquarium setup and many tanks sold as ‘reef-ready’ saltwater aquariums incorporate a sump.  Having a sump enables you to hide bulky equipment like the protein skimmer and phosphate reactor while increasing your overall water volume for more stability.  You can even add macroalgae and live rock to a sump to create a refugium.

Perhaps the only downside of a sump is the extra cost of running a return pump 24/7 to your main display tank.

Ready-Made Aquariums | Measurements

For the beginner starting out with a ready-made aquarium, a number of dimensions and gallonages are available.  Let it be said again that the greater the water volume, the more stable and tolerant of typical beginner’s mistakes the aquarium’s eco-system will be.

The following dimensions (length x width x height, in inches) are based on typical, commercially available ready-made aquariums:

20-inch Length Aquariums

20 x 10 x 12 (10 gallons)

36-inch Length Aquariums

36 x 12 x 16 (30 gallons)

36 x 18 x 12 (33 gallons, low or ‘breeder’ tank)

36 x 18 x 16 (45 gallons)

36 x 18 x 18 (50 gallons)

36 x 18 x 24 (65 gallons)

36 x 24 x 24 (90 gallons)

48-inch Length Aquariums

48 x 12 x 12 (30 gallons)

48 x 13 x 17 (45 gallons)

48 x 12 x 20 (50 gallons)

48 x 18 x 20 (75 gallons)

48 x 18 x 24 (90 gallons)

48 x 24 x 24 (120 gallons)

48 x 24 x 30 (150 gallons, ‘high’ tank)

60-inch Aquariums

60 x 18 x 20 (90 gallons)

60 x 24 x 24 (150 gallons)

72-inch Length Aquariums

72 x 24 x 24 (180 gallons)



More about Saltwater Aquarium Setups:

Aquarium Tank Size | Length, Width And Height

The Ideal Location For Your Saltwater Aquarium

Drilled Overflows Vs. Siphon Overflows

Aquarium Stands

Why Beginning Hobbyists Should Avoid Starting A Nano Aquarium

Aquarium Chillers

Aquarium Sump



Aquarium Covers | Put A Lid On It!

Cooling Fans


What You Don’t Need For Your Saltwater Aquarium!

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