New Homeowner/Member - Calculating Pool Size?

[muffin_dad]

Hi everyone, thanks for this forum, loads of information here. I got the TFT100 test kit so I have results to share and questions about those, but first I thought I should know the size of my pool. Previous owner doesn't really know (he guessed 35k-40k gallons). I'm including photos and measurements here in case there's some sort of calculation that can be done.

Pool is 8.5 ft deep to the water line in the deep end. Tanning shelf on the shallow end next to the spa. Spa is 7 ft in diameter with a seat all the way around.

 

[BoDarville]

Welcome to TFP!

I would use the Pool Math tool ( http://www.troublefreepool.com/calc.html). Towards the bottom of the page is an area for estimating pool volume. You will need to enter two separate sets of dimensions for your pool and spa and then add the two volumes.

Based on your pic, I would choose the "oval" option for the pool and then take the length/width dimensions and average out the pool depth (for example, if the shallowest part of your pool is 3.5 feet and the deep end is 8.5, average these two figures to get the depth).

For the spa , choose the "round" option and enter the diameter of 7 feet. For the depth, measure the depth to the shallow part (seating area), then measure the depth to the floor of the spa. Average these two figures for the spa depth.

BTW, congratulations on getting the TF100 . Will save you lots of $ by dosing only with the chemicals and amounts needed, not to mention the priceless aspect of a sparkling pool.

 

[muffin_dad]

Thanks for linking to that tool BoDarville - very helpful (is that really you Burt Reynolds?) I calculated the following:

Pool - 6.5 average depth (4.5 shallow end, 8.5 deep end), 17' wide, 36' long = 26,700 gal
Spa: 7' diameter, 4' depth = 1,200 gal

Total gal = 27,900

Sound about right? I'll post another thread for the levels based on current test results.

 

[Richard320]

Thanks for linking to that tool BoDarville - very helpful (is that really you Burt Reynolds?) I calculated the following:

Pool - 6.5 average depth (4.5 shallow end, 8.5 deep end), 17' wide, 36' long = 26,700 gal
Spa: 7' diameter, 4' depth = 1,200 gal

Total gal = 27,900

Sound about right? I'll post another thread for the levels based on current test results.

When you have accurate readings, pay close attention to what happens when you dose the pool. TA especially seems to work well for this. Be sure to wipe the tip of the R-009 so static electricity doesn't mess up the results. On http://www.troublefreepool.com/calc.html down near the bottom is Effects of Adding Chemicals. So let's say you need to lower pH and it tells you to add 30 oz of acid. Plug that in below and see what it says it will do to TA as well. Sometimes you can fudge a little and target a higher or lower pH to get TA to work out to a nice 10 ppm drop. Anyway, you do that and in a couple weeks you'll see that you're overshooting or undershooting, which will tell you the volume is higher or lower than you estimated. So adjust it up or down and see what happens over the next couple weeks. By Summer, you'll know within a couple hundred gallons how big your pool is, which will be close enough for dosing.

 

[muffin_dad]

Thanks Richard. Makes sense. As a type 1 diabetic for 30 years I have lots of practice doing this with my blood sugar, I figure the pool is just another thing to dose and measure, dose and measure, rinse and repeat...

 

[Divin Dave]

Man that's a killer pool you have there! The landscaping rocks too.

Is that some type of tall evergreen trees behind the diving board? If you dont mind sharing what type they are... those would worl perfect for a spot I have reserved for 'TBD'.

 

[muffin_dad]

Thanks! Sold us on the house, along with a few other features. Since I didn't plant them I'm not 100% certain but they look like Italian Cypress to me.

 

[BoDarville]

...I'm not 100% certain but they look like Italian Cypress to me.

Looks like Italian Cypress to me as well. I have five of them planted in our yard as a screen. Evergreen and very "clean" plants in that they don't drop debris into the pool.

BTW, your volume calculations look good to me. I recently re-ran my pool dimensions through the PoolMath tool (had calculated volume using another tool before I found TFP). Just updated my sig with the new volume which seems closer to actual.

Richard320 brings up a good point about paying close attention to what happens when you dose the pool after making the initial volume calculation. This will serve as a sanity-check on the volume measurement. In fact, this is what lead me to remeasure my pool's volume. Even though my water chemistry numbers were kept within the recommended ranges, it seemed that I needed to use a slightly higher dose to get/keep them there.

Over the next several dosing sessions, I would take measurements about one hour after dosing (with pump on) and see if the water chemistry numbers changed to what you were expecting based on your dosage amount. If the change is a bit less than you were expecting, then you are undershooting which indicates your pool volume is slightly higher than your estimate. If that's the case, increase your dosage slightly and record the amount. If the opposite situation occurs, decrease the dosage and retest. All of this assumes your pool chems are fresh and at the labeled potency. If there is any doubt, start with fresh chems. When you reach the point where your dosage amount has the expected impact on your water chemistry, you will have fine-tuned your pool water volume measurement.

 

[pwrstrk]

Welcome to TFP and congrats to the new home that beautiful pool ! ?

 

[Isaac-1]

Like the others said congrats, I love the look of the pool