# Thread: Calculating size of pool

1. ## Calculating size of pool

Hi!
We are testing our water every evening, putting numbers in PoolMath, and adding recommended amounts of appropriate chemicals (usually just bleach). Our pool water is absolutely gorgeous and feels so silky - the best it's ever been. This is our first year with TFP, and we are loving it!
My question is this: Every evening, our FC is about 2.4ish, so we add the recommended amount of12% chlorine. I was curious if it is ever getting back up to the FC goal of 6, so I just tested it toady at 1 pm and it is 3.2. Is it possible that our pool is bigger than we calculated (difficult to be precise with the deep end slope and oval shape)? Should we bump our size and therefore start adding more chlorine, or, since the water looks and feels so great, should we leave it alone and keep doing what we've been doing (don't fix iit if its not broken)? By the way, the pH has been consistently around 7.6. We test the other levels weekly (TA, CYA, and CH) and they have been consistently within goal range.

Thank you!
Jill

2. ## Re: Calculating size of pool

Im a stickler for specifics so I would try to calculate what the exact volume is.. If you don't have enuf chlorine in the water, it invites contaminate growth.
there is a calculation out there (cant remember where I saw it) that uses L x W x avg depth.. Ill look around for it until someone else beats me to it....

http://www.swimmingpool.com/maintena...ume-calculator
http://www.poolwizard.net/pool-volume/

3. ## Re: Calculating size of pool

There's also a chemical method for calculating pool volume but it does use quite a bit of your TA reagents -

A Chemical Way of Calculating Pool Volume

If done right, you only have to do it once.

4. ## Re: Calculating size of pool

PoolMath has this to say:

"If the depth varies, use the average depth of the pool. A good approximation is the shallow end depth plus the deep end depth divided by two. Irregularly shaped pools can be approximated by estimating the average length and width and using rectangular."

So I think a reasonable approximation using the calculator on pool math would be get average depth, then just give length and width of the oval.

5. ## Re: Calculating size of pool

Thank you for all the suggestions. We had already used the average depth method in our original calculations, so we will stick with that number. I hadn't heard of the chemical method…intriguing for sure. Hopefully, I think we're doing everything right.
A related question is how much does chlorine typically drop on very hot days?

6. ## Re: Calculating size of pool

Originally Posted by D&JButler
A related question is how much does chlorine typically drop on very hot days?
2-4ppm

7. ## Re: Calculating size of pool

Thank you, again, everybody. We test our water around 8 pm and add whatever is needed according to the PoolMath calculations. Awesome tool! We have our goal FC set at 6.
So, we checked the FC at 8 am the last 2 mornings, and it was 5.4 and 5.6. So we feel confident that everything is fine. We really, really appreciate all the encouragement, advice, information, and patience we find on this site!!! You guys are the best!!!

8. ## Re: Calculating size of pool

Have you tried this pool volume calculator from Pentair? Pool Volume Calculator | PENTAIR

9. ## Re: Calculating size of pool

Originally Posted by Marlahoutex
Have you tried this pool volume calculator from Pentair? Pool Volume Calculator | PENTAIR
That's a great tool! I measured my 16x32 oval pool volume by reading the water meter during fill at 13,200 gals. The Pentair tool (oblong option using oval measurements) calculates 13,392 gals. My gals/IN-depth is 320 gals. So the tool is very accurate in my simple situation.

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