Tank Capacity - Interpretation

[FEJ]

This, may be trivial but it has been bugging me for awhile. What is the standard interpretation for stating the size of your aquarium system?

I have a display tank measuring 96" x 27" x 30" in height. Also, I have a sump measuring 60" x 18" x 10" (average water level).

The water capacity of the system empty is approximately 1,452 L; 383 US gal; 319 Imperial gal.
But, my set up is not empty. It has a 2" deep sand bed, rocks, 20kg of bio filter media, plus minor displacement for sump equipment, fish, and refugium material.

Accounting for the above and deducting glass thickness and actual water level in the DT, I estimate the water capacity to be approximately 1,234 L; 326 US gal; 271 Imp gal.

So, if this was your system, what capacity would you go with?

 

[UncommonSense]

This, may be trivial but it has been bugging me for awhile. What is the standard interpretation for stating the size of your aquarium system?

I have a display tank measuring 96" x 27" x 30" in height. Also, I have a sump measuring 60" x 18" x 10" (average water level).

The water capacity of the system empty is approximately 1,452 L; 383 US gal; 319 Imperial gal.
But, my set up is not empty. It has a 2" deep sand bed, rocks, 20kg of bio filter media, plus minor displacement for sump equipment, fish, and refugium material.

Accounting for the above and deducting glass thickness and actual water level in the DT, I estimate the water capacity to be approximately 1,234 L; 326 US gal; 271 Imp gal.

So, if this was your system, what capacity would you go with?

You’ve stumbled on one of the industry’s little secrets here! The vast majority of aquariums are advertised by their outside dimensions (volume) not inside dimensions (capacity)…

Because (almost) the entire industry relies on the volume number (bigger) for reference purposes (ie. Sizing skimmers, minimum tank size for fish, etc..), it is the number you should typically work by to avoid confusion!

— however, for the purposes of actually doing water changes, dosing, etc; try to work out a rough estimate of your true operating system capacity for accuracy reasons!

— Usually, the tank ends up being roughly 1/8 smaller in capacity than the advertised size, though this varies based on wall thickness, overflow box size/configuration, and operating water height!

(I went so far as to actually fill my old acrylic hexagon tank when I go it from a measured volume of water to determine its exact capacity, knowing that manually calculating it otherwise would be a bit of a headache!)

 

[FEJ]

.

 

[FEJ]

You’ve stumbled on one of the industry’s little secrets here! The vast majority of aquariums are advertised by their outside dimensions (volume) not inside dimensions (capacity)…

Because (almost) the entire industry relies on the volume number (bigger) for reference purposes (ie. Sizing skimmers, minimum tank size for fish, etc..), it is the number you should typically work by to avoid confusion!

— however, for the purposes of actually doing water changes, dosing, etc; try to work out a rough estimate of your true operating system capacity for accuracy reasons!

— Usually, the tank ends up being roughly 1/8 smaller in capacity than the advertised size, though this varies based on wall thickness, overflow box size/configuration, and operating water height!

(I went so far as to actually fill my old acrylic hexagon tank when I go it from a measured volume of water to determine its exact capacity, knowing that manually calculating it otherwise would be a bit of a headache!)

Thank you for your explanation.

So, when referring to my setup in future posts, I should quote the empty system volume rather than the true system capacity when loaded?

I'm learning all the time.

 

[Ziggy17]

For anything important ie dosing, medication, I use the actual number (smaller one), but when talking about the tank in general, I use the figure given by the manufacturer.

I also use this. https://reef.diesyst.com/volcalc/volcalc.html

I just use the water level as the top dimension rather than the true top measurement.

 

[UncommonSense]

So, when referring to my setup in future posts, I should quote the empty system volume rather than the true system capacity when loaded?

Precisely! This can can start to lead to some comical disparities when getting into small, thick-walled tanks, but it’s just the way it’s always been done!

(I built a “35g” glass terrarium that was realistically more like 25g a few months ago, for example! And, because it’s for terrestrial hermit crabs which prefer a solid 6” of substrate, it is likely closer to 18-20g!)

 

[jsmkmavity]

The tank size is the outside dimensions for comparing to other tanks but the capacity is how much fits in it.

 

[jsmkmavity]

A 96 x 24 x24 is in the 240 gallon class but if built with 1" glass it can only hold 197 gallons filled to the bracing. Thats almost 20% less

 

[maroun.c]

Normally tank volume is the volum of the display tank glass measurement from outside. it gives an idea about how large your tank is.
For treatment purposes an as accurate calculation of the water volume is needed.