Measuring pool volume

[lavndrocean]

I’ve recently realized the two local pool stores by our house have two different volume amounts for our pool (they’re listed under the former owners so we’re still trying to work out getting to know our pool). One store has it listed at 11,000 and the other is 19,800; that’s quite a drastic difference. I’ve posted a photo of our pool w/spa. 1: For measuring purposes, would this odd shape be closest to rectangular or kidney?
2: Do we include the spa? If so do we measure that separately and then add those to the width/length/depth of the pool?

 

[Texas Splash]

I'd probably go with kidney. Since your signature is showing13K, just stick with that and then make adjustments based on how your chemical dosing goes. For example, if the PoolMath APP told you 1/2 gallon of chlorine would increase the FC by 5 ppm, but it only increased by 3, then your pool is probably bigger than 13K. By contrast, if your FC increased by 7 ppm, then your pool is smaller than 13K. So adjust the pool volume slightly and see how it goes the next time. Other than having an empty pool and filling from scratch while watching the water meter, that's one way I can think of.

 

[lavndrocean]

I'd probably go with kidney. Since your signature is showing13K, just stick with that and then make adjustments based on how your chemical dosing goes. For example, if the PoolMath APP told you 1/2 gallon of chlorine would increase the FC by 5 ppm, but it only increased by 3, then your pool is probably bigger than 13K. By contrast, if your FC increased by 7 ppm, then your pool is smaller than 13K. So adjust the pool volume slightly and see how it goes the next time. Other than having an empty pool and filling from scratch while watching the water meter, that's one way I can think of.

Perfect, thanks so much

 

[generessler]

@Texas Splash 's idea is fine. If you want to try for a better estimate on your own, get in the water with a tape measure and try to take one depth reading for every circular area of the pool with the diameter of your outstretched arms. Have someone record those readings. You need to include everything that holds water. It's going to be approximate. Just do your best. Add them all up and divide by the number of measurements. That's the average depth.

You also need the surface area. For that just gaze at the pool and imagine a rectangle that shoots the average of each curvy edge. Then get your tape again and figure out the length and width of that imaginary rectangle.

Get all the measurements into the same units. Say feet. Multiply the rectangle length, width and average depth. This gives cubic feet.

Now multiply by 7.48. That's gallons.

I had the same problem in reverse. No one knew the volume of our pool. I'm a software guy with OCD. I measured roughly as described above and wrote a custom program. If you're that crazy and a Python programmer, I'll be happy to share the details.

Yeah. I'm crazy.

 

[lavndrocean]

@Texas Splash 's idea is fine. If you want to try for a better estimate on your own, get in the water with a tape measure and try to take one depth reading for every circular area of the pool with the diameter of your outstretched arms. Have someone record those readings. You need to include everything that holds water. It's going to be approximate. Just do your best. Add them all up and divide by the number of measurements. That's the average depth.

You also need the surface area. For that just gaze at the pool and imagine a rectangle that shoots the average of each curvy edge. Then get your tape again and figure out the length and width of that imaginary rectangle.

Get all the measurements into the same units. Say feet. Multiply the rectangle length, width and average depth. This gives cubic feet.

Now multiply by 7.48. That's gallons.

I had the same problem in reverse. No one knew the volume of our pool. I'm a software guy with OCD. I measured roughly as described above and wrote a custom program. If you're that crazy and a Python programmer, I'll be happy to share the details.

Yeah. I'm crazy.
View attachment 436566

That’s hysterical because that was one of the ways we measured, including my getting in the pool (& spa) for each area’s depth and averaging that. I think we did no less than 3 different ways of measuring. Because ya know, the internet doesn’t have just one go-to method for anything, and I’m a teensy weensy ocd myself lol
I can’t remember off the top of my head if that was closer to 12,000 or closer to the 13,000 but it’s on my paper

 

[Toxophilite]

Not knowing the depths, but judging on a scale using the shrubs, I think it's going to be a good bit over 11K and maybe closer to the original number logged at the store. My chlorine adds via pool math have long suggested I'm off on mine by a few K, as I just went with what generic, eyeball, sizing the PB's crew would throw out. I tried at filling, but had to many variables on fill hose rates and late start in recording.

 

[lavndrocean]

After many attempts we finally reached the original pool contractor and they were actually able to find the file from 2003. The pool is 9472 gallons. I’ve rounded it up to 10k.
Boy, the pool stores were way off at 21k and only a little off at 11k. The Chems are currently still a bit high but I’m hoping we’ll continue to be able to walk it back a bit. I can’t believe I’ve been trying to balance it for so many weeks. The pool is clear, water feels great and I’ll just keep following PoolMath.