Aquarium Gallon/Model Ratings

Be Careful When Comparing Aquarium Brands

Aquarium Gallon & Model Ratings

There is a secret we need to tell you! Most aquarium manufacturers and resellers’ “gallon” ratings for aquariums are not an accurate representation of how many gallons the aquarium will hold. Some aquarium brands are not even close.

We have always found this to be a peculiar practice by most aquarium manufacturers and resellers to advertise aquarium brands as a particular number of “gallons” when the actual gallons of water it holds are not even close to what they advertise. We even find many instances where a reseller’s advertised rating does not match the aquarium manufacturer’s suggested rating of the aquarium brands they are selling!

Being an aquarium manufacturer ourselves, this put us in a difficult situation… do we just tell the customer the “actual” gallons the aquarium holds, which is usually a really odd number most people are not familiar with and really can’t compare to anything else, or do we advertise our aquariums just like most everyone else where we round up (way up in a lot of cases) to a number that sounds good but may be a little misleading?

We decided the best practice is to give you the customer as much information as possible so you can make the most informed decision. For this reason, all of our aquariums will showcase two ratings:

  • Actual Gallons: tells you the volume of water it can actually hold. Is more accurate for sizing your filtration and chemistry.
  • Model Gallons: a number that is more comparable to how other aquariums of a similar size would be labeled. Will help you compare our aquariums to other aquarium brands on the market.

Actual Gallons

Our “actual gallon” rating calculates the maximum capacity when filled all the way to the brim with just water, nothing else in the aquarium. The INSIDE height, length, and depth of the glass within 1/4″ in each direction are used to calculate this volume. Some other aquarium brands round way up, sometimes they use the outside dimensions of the glass, and some even use the outside dimensions of the frame or the stand even in their actual gallons figure. What good is it to include the volume of the glass or frame itself when that clearly does not hold water? We don’t know, we are still trying to figure it out. Some ratings are so far from reality it is hard to know where or how they came up with it. This difference can be significant, sometimes as much as 20% or more so it is important when comparing that you compare apples to apples. Sometimes accurate information is not so easy to find for other brands.

Model Gallons

To determine our “model gallons” rating we looked at some of the more common brands available, compare their actual height, length, and depth to ours, and came up with what we believe is a general industry consensus of what each size is commonly referred to.

Actual Functional Gallons

The actual functional gallons is the actual gallons used in each aquarium setup after you consider all displacement factors. When sizing your aquarium filters, capacity for livestock, and products you use to manipulate the chemistry, it is important to take into consideration all the displacement factors involved to determine how many actual functional gallons you are using. This will ensure the chemistry of your aquarium can be maintained at proper levels without overstocking or overdosing.

Dry Weight Rating

The dry weight rating is the approximate weight of the glass and frame, but does not include the weight of glass lids, packaging, or other interior or exterior items like hoods, stands, gravel, rocks, coral, filtration, decor, etc.

Full Weight Rating

The full weight rating is the dry weight rating of the glass and frame of the aquarium itself PLUS the weight if it were filled to the brim with water. Again, this does not include glass lids or anything else you may put inside the aquarium. Items like gravel, rocks, etc. are significantly denser than water and can make the overall setup considerably heavier if used, so please make sure you take this into consideration when accounting for structural loading requirements where this aquarium will be placed.

Possible Displacement Factors:

  • Keep in mind our “actual gallons” rating takes into consideration being full of water all the way to the top of the lid. In most instances, you will not fill your aquarium all the way to the top. There is usually an inch or so to spare, sometimes more.
  • Some “euro-style” aquarium brands use a significant amount of glass bracing inside of the aquarium for structural support of the aquarium. This can add up to a lot of displaced water.
  • Excessively large overflows can contribute to water displacement. The H2Overflow® aquarium overflow box is a great solution!
  • Gravel, rocks, plants, decor, and essentially everything else you put inside your tank will displace water.

A Cure for Displacement – Use a Seamless Sump®!

Our “actual gallons” rating takes into consideration being full of water all the way to the top of the lid. In most instances, you will not fill your aquarium all the way to the top. By the time you take into account all of the nuances of how much water you have displaced with your equipment and decor… it might seem like there isn’t nearly as much water as you think. Our Seamless Sump® system is a great solution. It keeps all of the maintenance equipment out of sight and out of mind in the stand of your aquarium, and at the same time adds significant water volume to help keep your system balanced and healthy! More Seamless Sump® aquarium system information.