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cm11599ps
06/05/2011, 07:40 AM
I'd like to calculate how many gallons are in my assorted cans. I have one Brute can that functions as my ATO that I'd like to dose my mag into. I believe the can states it's a 32 gallon can. I also have 2 Home Depot orange buckets that are supposed to be 5 gallons.

I found an online calculator and it states my 32 gallon cans can actually hold around 38 gallons if filled to the top. It states the HD buckets can hold 6 gallons when filled to the top.

Here's the too. Do you think it's an accurate figure? http://www.theaquatools.com/volume-calculator

frankpayne32
06/05/2011, 08:02 AM
volume of a cylinder = pi x radius squared x height. Use inches for the height and radius and that will give you an answer in inches cubed. Then multiply that number by 0.00432900433 to get an answer in gallons. This will give you a precise answer.

Rybren
06/05/2011, 08:08 AM
Remember that the brutes are not true cylinders - they are narrower at the bottom. Therefore, if you use the bottom radius, the calculated volume will be lower than the actual. If you use the top radius, the calculated volume will be higher than actual.

sirreal63
06/05/2011, 08:26 AM
Rybren is right and the solution is take the diameter from the middle of the Brute, as it decreases at the same rate it increases, so the middle is close to accurate.

To make calculating volume easier, I use this one.

http://reef.diesyst.com/volcalc/volcalc.html

snorvich
06/05/2011, 09:49 AM
volume of a cylinder = pi x radius squared x height. Use inches for the height and radius and that will give you an answer in inches cubed. Then multiply that number by 0.00432900433 to get an answer in gallons. This will give you a precise answer.

Exactly. Remember that most things you buy, e.g. Brutes are not truly cylinders. However, if you measure the bottom radius squared times pi and then similar for the top, you can approximate by taking the total height times the average of the two circular areas.

noahm
06/05/2011, 10:10 AM
Exactly. Remember that most things you buy, e.g. Brutes are not truly cylinders. However, if you measure the bottom radius squared times pi and then similar for the top, you can approximate by taking the total height times the average of the two circular areas.

You like to make work for yourself ;) the middle diameter will do as the D-average rather than calculating out average areas.:)

Funny thing is, all my early life they rammed pi*r^2 down our throats, but engineers all use pi*d^2/4 since, really who measures a radius?

To the OP, remember as well, that these containers are designed for a certain fill height (often one of the support rings), so they will usually hold a bit more than specified if filled to the brim.