# Freeware volume calculator for irregularly shaped pool

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• posted on July 17, 2010, 4:27 pm

What good is calculus if nobody practically uses it. My pool has an uneven bottom (shallow and deep and varying greatly).
All pool-volume calculators I can find assume a gently sloping bottom (and therefore use geometric simplifications). I want to try a calculus based pool volume calculator (that takes the actual shape of the bottom curve into consideration).
To obtain an accurate pool water volume, I just measured in two dozen places every few feet the varying depth of an irregularly shaped pool.
I realize, with those numbers, I can draw a side view and then break it into squares to calculate the volume but there must be a calculus volume calculator out there that will take the shape of the bottom curves.
But since this is a common need of every pool owner of an irregularly shaped pool, I wonder if there is a good freeware calculus (not geometry) pool volume calculator out there that you recommend.
Googling, I found these two Windows freeware volume applications: * AD Geometrical calculator http://www.filetransit.com/view.php?idG49 * Volume Calculator http://www.freewarefiles.com/Volume-Calculator_program_43621.html
And, of course, there are the generic geometric pool-volume calculators (which all suffer from geometry assumptions): * http://www.pentairpool.com/pool-owner/resources/calculators/pool-volume-calc/poolcalc.htm * http://www.poolspa.com/calculator / * http://www.poolwizard.net/pool-volume / * http://www.backyardcitypools.com/swimming-pools/Pool-Volume-Calculate.htm * http://www.poolandspachemicals.co.uk/volcalc.htm * http://www.havuz.org/pool-calculators.htm * http://www.poolfactoryonline.com/tutorials/pool-volume-calculator * http://poolways.com/volume.html
What good is calculus if nobody uses it? Do know of any volume calculators that will take the shape of the pool bottom (measured in two-foot increments) into consideration accurately without geometric simplification?
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• posted on July 17, 2010, 4:41 pm
LM wrote: ...

Well, I guess that characterization would ignore a fairly size of population to "nobody"... :)

Octave comes to mind as one toolset...
A relatively simple approach would be to use the data to estimate a quadratic or cubic polynomial which could be integrated analytically.
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<%-name%>
• posted on July 17, 2010, 5:07 pm

Scientists for years have used graph paper for estimating. Here's how it works: draw a side view of your structure on graph paper using physical measurements that are convenient. Cut out the outline of the view with scissors and weigh it. The scientist will use a sensitive microbalance in most cases which you may not have access to. So the variation here is to use a piece of scrap sheet metal or plywod, particle board, or such, with a scribed-on grid, lay out the side view, cut it out and weigh it on any convenient scale. Many retail places have scales the public uses for produce, and such...talk to the manager. Even a bathroom scale could work. Knowing the weight of a measured piece of the pattern material, the area of the side view is easily calculated. From there, measurement of the next two sides will give a decently accurate volume. For accurate distance measurements I highly recommend one the new laser measuring tools like the Bosch DLR 165K. Have fun...
Joe
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<%-name%>
• posted on July 17, 2010, 5:10 pm
On Sat, 17 Jul 2010 09:27:32 -0700, LM wrote:

Never heard of a calculus algorithm?

Try calculating hyroflows of rising tides in a 2500 acre+ mangrove swamp then. lol
--

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• posted on July 17, 2010, 6:11 pm

(snip)
Why do you imagine that every owner of an irregularly shaped pool needs to know how much water it takes to fill the pool?
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• posted on July 17, 2010, 6:13 pm
On Sat, 17 Jul 2010 14:11:12 -0400, "JoeSpareBedroom"

Gee......Woudn't that stuff be in the manual?
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• posted on July 18, 2010, 1:54 pm
On Sat, 17 Jul 2010 14:13:57 -0400, Metspitzer wrote:

Yup, he should go find the manual or even download it. It should have this information since pools are involved in many civil suits.
--
Thus spake the master programmer:
"Let the programmers be many and the managers few -- then all
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• posted on July 18, 2010, 4:34 pm
On Sun, 18 Jul 2010 09:54:10 -0400, Rocinante wrote:

At first I thought he was joking so I ignored the "get the manual" advice.
But now, with a second person saying this, I must ask how does one "get the manual" for a pool?
The pool was probably built about ten years ago by the owners at that time.
I've long ago downloaded the manuals for each piece of equipment, each of which has a brand and a model stamped on it. But how do you download a manual for the pool itself?
The pool doesn't have a "brand" or a "model" - or does it?
Where do you look for the brand or model or serial number on a pool?
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<%-name%>
• posted on July 19, 2010, 11:04 am

Never mind the manual. Please answer the question which frightens you the most, which is why you're avoiding it:
Why do you imagine that every owner of an irregularly shaped pool needs to know how much water it takes to fill the pool?
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<%-name%>
• posted on July 19, 2010, 3:03 pm
On Mon, 19 Jul 2010 07:04:08 -0400, JoeSpareBedroom wrote:

I followed the advice here, which was to break the pool into short segments of uniform slope and then just calculate the volume assuming the average of the depths.
So, at 1-foot increments, I gathered all the data into an OpenOffice freeware spreadsheet. There were about seventy-five measurements, given the irregular nature of the floor but I think I have it down to almost the exact gallon as I took into account everything.
If I went to the best pool calculator I could find (and I tested them all!), it was off by about a thousand gallons. That's a LOT! http://www.pentairpool.com/pool-owner/resources/calculators/pool-volume-calc/poolcalc.htm
None of the supposed freeware programs worked. One was decidedly not freeware (their web page was a lie). The other didn't do as advertised.
There are many reasons for wanting to know the gallons in the pool. Due to our location, we need to get water trucks to fill the pool. Also, we pay water bills based on percentages of a baseline, the more you go over the baseline, the more you pay. With judicious juggling of the trucked-in water and the monthly use of the hose, we can avoid additional charges.
Right now the pool is filled so I don't need the water trucked in, but that's why I wanted to know how much water is in the pool. The trucks only carry so much you know (I guess the next question is how many gallons in the truck, but I assume the water company knows all that.) :)
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• posted on July 19, 2010, 3:19 pm

http://www.pentairpool.com/pool-owner/resources/calculators/pool-volume-calc/poolcalc.htm
If you have to think about the cost of water, you have no business operating a pool.
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<%-name%>
• posted on July 19, 2010, 3:56 pm
On Mon, 19 Jul 2010 08:03:27 -0700, LM wrote:

calc/poolcalc.htm
Dear me, I've been watching this thread with interest (disbelief)
As an old civil engineer who had to do earthwork calcs, do a search for "prismoidal calculations" first hit on google <http://www.alamo.edu/sac/engtech/CADD/psencik / Civil_Volume_Calculations.pdf>
A 1000 gallons is only a lot when taken as a proportion of the total volume.
How much does a water truck carry. Depends on the truck. Do they not have the capacity shown on the truck in the states?
1000 US gallons = 3.79 cu.metres so it is a little less than 4 tons in weight. say, quarter of a small tanker or 1/10 of a big tanker.
--
rich

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<%-name%>
• posted on July 17, 2010, 8:13 pm
This isn't really a calculus problem.
If you have an equation that describes the x-y-z coordinates of the bottom of the pool, then... you can turn it into a calculus problem.
What you have to do is your own version of "integration". It sounds like you've done it part way already by measuring the depth at many locations.
The only thing you can really do is split the "plan" view of your pool into smaller areas. Then... measure the average depth for each individual area. Volume = Summation of all Area*AvgDepth. If your area calculations are correct and your average depth measurements are exact, your volume calculation will be exact. Otherwise... you merely have an approximation.
A lot of pools only vary in depth as you cross from one end of the pool to the other. ie... they don't vary across the other direction of the pool. If this is your situation, merely divide the pool into strips across the pools width. Then apply the above method using each strip as an area. This would yield pretty good results with very little effort.
I'm an engineer. I use Calculus for a lot of things and have found it to be EXTREMELY useful. It is used in just about every industry there is. When my wife, who does accounting work, was wondering where one of the formulas she was using came from that is widely used in the finance industry and has square roots and other things in it.... I was able to quickly and simply use basic calculus to show her how to come up with the formula. If you love using your iPhone or any other cell phone, fancy or not..... I'd venture to say that.... you wouldn't have that phone if calculus (or something similar) had never been invented. Heck... calculus is even used to figure out the most efficient way to package items together for shipping.
Dan :-)
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• posted on July 17, 2010, 8:13 pm
On 7/17/2010 12:27 PM, LM wrote:

Really? that would be big news to a lot of folks who use calculus in their work.

http://www.pentairpool.com/pool-owner/resources/calculators/pool-volume-calc/poolcalc.htm
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• posted on July 17, 2010, 9:09 pm

No. But since you've made the depth measurements in two-foot increments, just carve up the pool into those two-foot solids. Calculate the volume of each solid and add 'em all up.
A little tedious but it shouldn't take long.
It's going to be pretty much as accurate as you can get from the available measurement data.
--
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| Malcolm Hoar "The more I practice, the luckier I get". |
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• posted on July 17, 2010, 10:07 pm
Malcolm Hoar wrote:

I found the OP rather surprising. Though to be fair, both my kids (in their twenties and thirties) would be flumoxed.
Whilst struggling under a motor asking for an 8 mm. socket from them would challenge them. Asking for a 1/2" Whit or an AF would ensure that they signed up to the Chattering Classes.
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• posted on July 17, 2010, 10:53 pm
On Sat, 17 Jul 2010 21:09:45 GMT, snipped-for-privacy@malch.com (Malcolm Hoar) wrote:

Enter the depth measurements for each two-foot square into a spreadsheet. Sum all cells and multiply by the size of the square (four, in this case) and convert to the unit of choice (times 8 for gallons).

Not at all. ;-)

Yep. As another poster said, he doesn't have the equation to fit the bottom of the pool so it's not a calculus problem.
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• posted on July 18, 2010, 6:57 am
On Sat, 17 Jul 2010 09:27:32 -0700, LM wrote:

Neither of which is freeware that performs pool volume calculations.
The first is trial ware and it doesn't do pool volumes with slopes.
The second is a cylindrical volume calculator.
What you need does not exist.
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• posted on July 18, 2010, 3:50 pm

Well, it does (or did) but not as freeware. Many moons ago (circa 1987) I was involved in marketing a software product called PDGS. This program was originally developed by Ford and primarily it was used to design and model shapes with double-curved surfaces. But it would also calculate the volume of a very complex shaped gas tank, for example.
One time at a trade show, we demoed this feature to a manufacturer of perfume bottles. We designed an elaborate bottle, clicked the button and we had the volume. It blew their socks off -- they told us it took them two weeks to do these volume calculations manually with the precision required. I believe they subsequently spent some big bucks on a license for the software.
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| Malcolm Hoar "The more I practice, the luckier I get". |
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• posted on July 18, 2010, 12:52 pm
LM wrote:

http://www.pentairpool.com/pool-owner/resources/calculators/pool-volume-calc/poolcalc.htm
You have a nail and are looking for a screwdriver.
Calculus doesn't deal with random measurements. You must first write the equation for the curve of the bottom.
THEN you can integrate over the range.
If you don't want to do that, look up MONTE CARLO METHOD.