Calculating tank volume

[Mark Hewitt]

I'm looking to buy a second aquarium and the one I'm looking at, unlike pretty much every fish tank, doesn't specify the capacity in litres (or gallons)

http://www.onlineaquariumstore.com/acatalog/Clearseal_18___X_10___X_10___All_Glass_Tank_Single.html

It just says the dimensions are 18" x 10" x 10"

Now it's pretty easy to work out that this is 1800 cubic inches, each cubic inch is 0.0164 litres so this tanks capacity should be 29.5 litres? Right?

But then presumably that's the outside dimensions, how much should I be deducting from that to get the true internal capacity?!

 

[mgamer20o0]

just have to measure the inside. small tank like that the glass is thin. the difference wont be too much.

 

[Mark Hewitt]

just have to measure the inside.

I don't have physical access to the tank! I'll be buying online.

small tank like that the glass is thin. the difference wont be too much.

Cheers, so if the outside dimensions give 29.5 litres, I can assume it's going to be around 29 litres

 

[mgamer20o0]

well when you get it you can figure it out. mind you... you should also take into account the substrate and other decor most people dont you already ahead of the curve.

 

[Mark Hewitt]

well when you get it you can figure it out. .

Well I need to know the tank volumes *before* I get the tank so I can make a choice as to which will be best.

I'm between two at the moment, the 18x10x10 29 litre tank which is perfectly sized and will fit in well where it's going to go. And the 18x12x12 42 litre tank which will look a little large, but would provide much more room for the fish! (There's also the issue that I've already gone ahead and bought the filter for the smaller tank and it'll be inadequate for the 42 litre one!)

 

[cmor1701d]

You already have a "close enough" estimate to make a choice.
I'm pretty sure tanks are based on the outside dimension for volume and always hold a bit less than what they are sold as.

 

[BigJim]

+1 for cmor. If you want a better estimate, take the outsides and knock half an inch (1/4" per side) off the length and the width measurements to account for glass thickness.

 

[jsoong]

If this is a glass tank, you also have to account for the dead space under the bottom pane. The bottom pane is usually raised up 1/2-3/4" from the bottom, decreasing your internal vol.

Assuming glass thickness of 1/4" (commonly used for this size tank), I say a good estimate would be 17.5x9.5x8.5 which is approx 6 US gal or ~24 liters.

Note that the water depth is decreased by 1.5 to account for the dead space in the bottom, the glass thickness, and a bit of headroom (since you can't fill the tank right to the brim ... you need to leave 1/2" or more on top as well!>

 

[Mark Hewitt]

I found a data sheet pushed inside one of the tanks in the store and it said the volume was 27.7 litres. Which is pretty close!