Gallons?

Richard320

TFP Expert
LifeTime Supporter
Jan 6, 2010
20,436
San Dimas, CA (LA County)
Break out the tape measure.

If it's rectangular, round, or oval, poolmath can do the math for you, down at the bottom. If it's more freeform, then you'll need to make a sketch and get dimensions and depths and calculate it in sections.
 

rkoustas

New member
Jan 30, 2017
4
Goodyear, AZ
Hello all, so how do I figure how many gallons is my pool?


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If you know the pool builder, they may have records. The previous owners left the pool builder's contact information. I just called them, gave my address and they looked it up...

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spinPHD

Well-known member
Apr 20, 2017
500
Phoenix
A couple tricks I have used to figure out my pool in gallons.

1.) If you ever decide to drain your pool, before refilling put the hose(s) that you use to fill your pool into a 5-gallon buck and determine how long it takes to fill the bucket. Then when you fill the pool, keep track of the time when you start and finish the fill. You can then calculate how many gallons your pool is based upon how long it took you to fill it up.

2.) An even easier method is to determine size based upon how much your FC raised after adding chemicals. Using your test kit, test your water and log it all into the pool calculator. Do a best guesstimate as to the size of your pool. After testing, add the exact FC it tells you to add in order to get to your target FC. Circulate water for about an hour, then test your FC levels again and determine how much your FC level actually raised. Go back to pool calculator and under "Effect of Adding Chemicals" plug in the amount of chlorine you had added. Now play around to the pool size in the calculator until the "effects of adding chemicals" matches your actual change in FC level. I would do this at night, since you don't lose chlorine during the hour you circulate the pool. Also, try to use a fresh batch of chlorine.
 

jeffbrig

Well-known member
Sep 24, 2014
146
Fort Lauderdale, FL
2.) An even easier method is to determine size based upon how much your FC raised after adding chemicals.
....
Also, try to use a fresh batch of chlorine.
Glad you mentioned freshness of chlorine. In reality, I don't think you can draw accurate conclusions, because even "fresh" chlorine may not have been stored in ideal conditions, and may not reflect the strength printed on the bottle.
 

borjis

LifeTime Supporter
Aug 19, 2014
2,711
Pacific NW
A couple tricks I have used to figure out my pool in gallons.

1.) If you ever decide to drain your pool, before refilling put the hose(s) that you use to fill your pool into a 5-gallon buck and determine how long it takes to fill the bucket. Then when you fill the pool, keep track of the time when you start and finish the fill. You can then calculate how many gallons your pool is based upon how long it took you to fill it up.

2.) An even easier method is to determine size based upon how much your FC raised after adding chemicals. Using your test kit, test your water and log it all into the pool calculator. Do a best guesstimate as to the size of your pool. After testing, add the exact FC it tells you to add in order to get to your target FC. Circulate water for about an hour, then test your FC levels again and determine how much your FC level actually raised. Go back to pool calculator and under "Effect of Adding Chemicals" plug in the amount of chlorine you had added. Now play around to the pool size in the calculator until the "effects of adding chemicals" matches your actual change in FC level. I would do this at night, since you don't lose chlorine during the hour you circulate the pool. Also, try to use a fresh batch of chlorine.

This is EXACTLY how I figured out my pool capacity. The pool co swore it was 15k but it turned out to be 13k using both methods above.
 

spinPHD

Well-known member
Apr 20, 2017
500
Phoenix
Glad you mentioned freshness of chlorine. In reality, I don't think you can draw accurate conclusions, because even "fresh" chlorine may not have been stored in ideal conditions, and may not reflect the strength printed on the bottle.
It's not exact, but if you do it every so often you can fine tune it to be pretty close. I think with every test you run, the more you learn about your pool and that includes getting a better sense of the actual size. After all, even if you know the exact size of pool you're never going to know the exact concentration of every bottle of bleach you add.
 

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