How do you measure aquarium sizes?

[GregDoug]

I ordered a new tank that was 280 gallons that is 72x30x30 but when I measure the inside volume, it is only 68x26x28 so the volume is like 60 gallons less. Is this right and the outside is the measurment? If so, why do we call it a 280 when it is only a 240 or so once it is made? I had the tank custom ordered from IA so I just wanted to make sure I did not get the wrong tank since the outside measurments with trim is about 72x30x30

[VegasMike]

Generally speaking, when people refer to measurements they are almost always outside dimensions. It really does not make much a difference when talking gallons until tou get to the bigger tanks.

The tank I just received has outside glass dimensions of 96"x36"x32" which works out to be around 480 gallons, but it is really more like 415.

That's just one of the quirks in this industry/hobby.

[Nagel]

I had the same question. My tank is a 96L x 30T x 24W tank with 1/2" acrylic. Is it a 275 (actual volume) or a 300. Most agree, its based on outside dimensions, even though theres 25 gallons worth of acrylic in there.

[GregDoug]

Thanks for the posts. I was just a little confused since the tank was about 20% smaller than I had thought

[Nausicaa]

I think the whole thing is really over rated. For crying out loud they charge you for a (what-ever sized tank) so why can't you just say you have that. Its what you paid for right? On the 1000 gallon tank it turned out to be a lil over 100 gallons less!!!

[AuroraDave]

I have 200+ pounds of live rock and 350 pounds of live sand displacing water too