Help on calculating gallons that our pool has

[cflannagan]

Noticed that profile signatures around here show total gallons in their pool. How can I calculate that for our pool?

Our pool is mostly rectangular, but has a spa above pool level in a corner (waterfalling into pool from spa). In the opposite corner, is a step into the deep end of our pool, and this corner is "cut off" from the rectangle.

I would probably just begin with this formula:

Length x width x ( ( depth of deep end + depth of shallow end) / 2)
To give me volume of our pool in cubic feet. Just need this converted to gallons. Would this suffice, or should my calculation be more precise for that when I share this information to local pool supply stores, this forum, etc?

Thanks in advance!

 

[cflannagan]

adding photos for clarity to what I am referring to

 

[woodyp]

Have you seen the gallons calculator in the pool calculator in pool school?

And you gotta allow for how much that gator drinks in a day too!

 

[cflannagan]

Yes - the link was down previously - now it's back up. :-D

Our pool is 13.5 x 30, and depth is an estimate (3 feet shallow end, 8 feet deep end, to make average depth about 5.5), it came out 16,700 gallons. However, our local store has a history on our pool from previous house owners and it is shown as 20,000, so I'm not sure if that is an estimation as well. There is a 2,300 gallon difference here - is 2,300 gallon difference significant when discussing what chemicals to buy for our pool maintenance needs?

I guess that gator drinks 2,300 gallons, lol.

 

[woodyp]

There's about a 1500 gallon difference from what the pool calc says mine is vs. what the manufacturer says. Split the difference and treat for that-should give you a real good idea on the FC test. Got a TF-100?
Those "local store" numbers are probably the worst ones.

 

[RobbieH]

I ran the numbers with the calc to get close, then treated according to the pool calculator. I adjusted the gallons for the pool until it matched what I was feeding the pool in chlorine. Probably more accurate than using the measurements!

 

[cflannagan]

I ran the numbers with the calc to get close, then treated according to the pool calculator. I adjusted the gallons for the pool until it matched what I was feeding the pool in chlorine. Probably more accurate than using the measurements!

Sounds like something I want to do, but I'm not really following - can you expand a bit about this methodology? Thanks in advance

 

[PaulR]

I ran the numbers with the calc to get close, then treated according to the pool calculator. I adjusted the gallons for the pool until it matched what I was feeding the pool in chlorine. Probably more accurate than using the measurements!

Sounds like something I want to do, but I'm not really following - can you expand a bit about this methodology? Thanks in advance

The idea here is that adding a known amount of a chemical will have a predictable effect on your test measurements. For example, if you add 1 gallon of 5.5% bleach to a 10,000 gallon pool, your FC will increase by 5.5ppm (until it gets eaten by sunlight or algae). Assuming you have a clean pool and you do this in the evening, if you have to add 1.5 gallons to get a 5.5ppm increase, then you must have 1.5 x 10,000 = 15,000 gallons in the pool.
--paulr