Pool number of gallons : getting it right

[AnalogHubris]

I used salinity to calculate mine as it is one thing that is a fairly stable measurement and you can find digital meters to read it

Teach me sense - I’m adding salt to my pool this week. Perfect window to figure out exactly how many gallons I’m working with

 

[wireform]

Teach me sense - I’m adding salt to my pool this week. Perfect window to figure out exactly how many gallons I’m working with

You want to make sure what the salinity is in the water before you introduce more salt as most chemicals added to the pool water contain some amount of salt and you may have a good amount.
Test Kits Compared The TF-100 pro has the needed K-1766 salinity test kit which is probably one of the most reliable test to date.

 

[AnalogHubris]

You want to make sure what the salinity is in the water before you introduce more salt as most chemicals added to the pool water contain some amount of salt and you may have a good amount.

Test Kits Compared The TF-100 pro has the needed K-1766 salinity test kit which is probably one of the most reliable test to date.

Yes - I got the pro kit and tested salinity of 400ppm. How do you used pounds of salt added with measured salinity change to determine gallons of water. Is there a calculator for it?

 

[wireform]

3200 ppm average salinity for SWCG. You have 400 so you need to add for 2800ppm. Each 40lb bag yields 185 ppm with 26k pooll volume. 2800÷185 =15 bags of salt.

 

[Mdragger88]

Salt is easy to overshoot (requiring draining if too high) so not the best method for estimating volume. Also salt takes days to fully be distributed.
Using ph measurements before & after acid additions & comparing them to
PoolMath estimates is a better & simpler bet to help hone things in.
There’s also a simple calculator here at the bottom of this page

PoolMath

Discover the calculator behind the perfect pool, PoolMath. Dealing with pools has allowed TFP to become the original authors of the best calculator on the net.

www.troublefreepool.com

& this one

Pool Volume Calculator

Check out Pentair's easy-to-use pool volume calculator to calculate the volume of your swimming pool water by choosing the shape, dimensions and depth.

www.pentair.com

Along with a more technical option

A Chemical Way of Calculating Pool Volume

There is a way to use pool water chemistry to calculate pool water volume without using the traditional geometric calculations. The geometric formulas are fine for pools that are traditionally shaped. However, when pools do not fall into these convenient shapes, a chemical method can be used...

www.troublefreepool.com

 

[PoolStored]

Salt is not a good chemical to use to get pool volume because the test is in increments of 200.

Make your pool size adjustments with chlorine or Muriatic acid.

When you need to make an adjustment, Test. Add your chlorine or muriatic. Circulate the pool for 30 minutes. Test again.

If your after results went too far, REDUCE the size of your pool by 500 gallons in pool math.
If your after results didn't go far enough, INCREASE the size of your pool by 500 gallons in pool math.

Rinse and repeat (you may need to wait until you NEED to add chemicals again) until your actual results are the same as expected results. When they are the same, your volume is correct enough.

 

[sande005]

I'd argue that salt, CL or TA would be a bit better for estimating use. pH and CYA depend on subjective estimates of perception changes (what color is that?, did the dot disappear there?)
The three drop tests are better when starting from high levels (more drops to make a change). But none are all that precise to allow a one time calculation. Best to sneak up on it. For mine, I assumed it was roughly 25K gal to start. Added what Pool Math said to to get the result. Oops, result was a bit low. Changed pool amount to 20K, now result was too high. Ending at using 23K gets me close enough for all future additions.
As noted, CL gives the fastest cycle time, is subject to environmental swings, but is self correcting if you go a bit over (given time for it to come back down). Salt is hard to bring back down, and TA gets messy trying to chase with soda and acid.....

 

[Mdragger88]

I'd argue that salt, CL or TA would be a bit better for estimating use. pH and CYA depend on subjective estimates of perception changes (what color is that?, did the dot disappear there?)
The three drop tests are better when starting from high levels (more drops to make a change). But none are all that precise to allow a one time calculation. Best to sneak up on it. For mine, I assumed it was roughly 25K gal to start. Added what Pool Math said to to get the result. Oops, result was a bit low. Changed pool amount to 20K, now result was too high. Ending at using 23K gets me close enough for all future additions.
As noted, CL gives the fastest cycle time, is subject to environmental swings, but is self correcting if you go a bit over (given time for it to come back down). Salt is hard to bring back down, and TA gets messy trying to chase with soda and acid.....

Using Muriatic acid & ph measurements is preferable as ma isn’t as susceptible to degradation like chlorine thus it removes a variable there.

 

[sande005]

Using Muriatic acid & ph measurements is preferable as ma isn’t as susceptible to degradation like chlorine thus it removes a variable there.

Perhaps, if one has a pH meter that actually works. Using the color scale can be pretty imprecise, but is doable if you are willing to chase it a few more times to zero in on the derived gallonage. Any of the measurements can be made to work, just go low and slow, especially for those hard to recover from if too much is added.

 

[AW139]

I found chlorine the easiest to estimate with, but as others have said the degradation is hard to guess. I used 10% chlorine from a large vat at my supplier, so it should not have degraded much. After starting at a guess of 10,000 gallons, I came to figure out using liquid chlorine addition and 0.2 test results my pool was about 8,000 gallons. Later on, I contacted my pool manufacturer and they told me my pool is 30,500 litres (8057 gallons), so it was a Dang close estimation.