[Lifer374]

Anybody out there happen to know what the true aquarium volume is for a standard 75?

[AS fan]

79 us gallons and 66 uk gallons per the calculator on this website for the 4ft tank. look under information tab at the top and there is a calculator there for it which is the one i used.

[Lifer374]

79?
Do you mean 69?

I know about the calculator, I just don't have a tape measure at my house right now. lol.

Thanks for the reply

[AS fan]

said 79 for a 48 by 18 by 21 which is a standard 75

[Lifer374]

Found a tape measue.

True aquarium volume for a standard 75 gallon tank at full water capacity with no gravel is roughly 70 US gallons.

[the_w8]

I was told that the actual dimensions of a true 75G were 78G and full off water minus substrate was something like 72. Not that it really matters, but this is what I heard.

[philbert]

the formula is LxWxH divided by 231 so 48x18x21 = 18144 then 18144/231 = 78.545454545454

so its 78.5 gallons

[Lifer374]

You guys are doing your math according to the outer dimensions which is why your not getting correct answers.
Inner dimension measurements is what you need to figure out what a tank really holds.

[philbert]

you don't need a tape measure to figure this out.

my 75 gal is made with quarter inch glass.

so 17.5x20.5x47.5 = 17040.625/231 = 73.76893939393939 gallons.

[Lifer374]

you don't need a tape measure to figure this out.

my 75 gal is made with quarter inch glass.

so 17.5x20.5x47.5 = 17040.625/231 = 73.76893939393939 gallons.

I don't like eye-balling.
And you don't get 20.5" from the floor of the tank to the inner lip of the top. Getting the height isn't the same as subtracting a half inch for glass thickness like you do for length and depth. Thats only 19.5" if you measure it.
The top/bottum tank frames are decieving.

With my measurements its 70 gallons max. And thats with no gravel at all and with the water level touching the inner lip of the top. Most of us keep the water around a half inch below that and have an inch or two of gravel at the bottum.

I'd say with gravel most of us have around 68-69 gallons of water in these tanks.


Your length and depth messurements are correct. Height isn't. You're an inch off.

This post has been edited by Tango374: 08 November 2009 - 12:22 PM

[philbert]

whatever i was just trying to help you out bc you said you don't have a tape measure, but apperently you found one since you went with your measurements. i got 70.3 gal when measuring from sand to lip. but if EXACT water volume is what you are looking for then. you gotta take into acount deco and fish too. why do you need such a precise number?

[Lifer374]

whatever i was just trying to help you out bc you said you don't have a tape measure, but apperently you found one since you went with your measurements. i got 70.3 gal when measuring from sand to lip. but if EXACT water volume is what you are looking for then. you gotta take into acount deco and fish too. why do you need such a precise number?

I appreciate your help too phil. Thank you.

Trying to get as precise as I can for dry ferts dosage.