Pool capacity calculation ?

Emarshbuck

LifeTime Supporter
Aug 3, 2013
175
Hilton Head, SC
We bought a house two years ago with an in ground pool. Pool is 22 yrs old, can't find original installer.

I have had several pool companies give me their opinion as to the # of gallons and they estimates range from 5,000 to 7,500. It's kidney shaped, 10' X 20'. Deep end is 5' , shallow end just shy of 3'.

Anyone have an idea how I can narrow down the capacity range?

Thx

Ed Marshall
 
Welcome to tfp, Emarshbuck :wave:

I am getting closer to 5000 gallons, but a picture would help. Regardless, if you use 5000 gallons when calculating dosing (most of us use poolcalculator.com for that), overtime you will get a feel for if that is close or not by tracking what you thought you dosed to compared to what your test says the pool is at.
 
If you pay strict attention to what you're adding to the pool and how it affects the chemistry, over a period of time you will be able to tell how big the pool is. Effects of Adding Chemicals in
http://www.poolcalculator.com/ is really useful.

In my case, TA reduction worked best. So the next time you need to lower pH, plug the dose in and see how much the acid will affect TA. You might even increase or reduce the dose to get a nice even multiple of ten. The next time you check, see if you got that result. Increase or decrease the pool volume in the calculator and eventually you will find the magic number that gives the predicted results on all the chemicals. It might take a month or more, but you'll get there.
 
Emarshbuck said:
Linen,

Here is a pic of pool. Still thinking 5k gallons?

Thx

Ed
I thinking it might even be less seeing where it is cut in. I am guessing more like 4300 gallons. I assume the deepend is furthest in the picture and that is where it is 10 ft wide? What are the widths at the center and shallow end? Is it a steady transition from 3 to 5 feet depth?
 
Linen

Sorry to take so long to reply. The deep end (top of pic) is the 10' wide section, shallow end is 8' wide. Water is crystal clear, FC dropped too low a day or so ago, had to brush algae off the sides, looks like DE filter has captured most of it. Still using fist size chlorine sticks in floater, pic attached.
 

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With those dimensions, I would guess it's around 4300 gallons.

The trichlor sticks you are using appear to be 8 ounces each. Each one is raising your cya 7.7 ppm. To get up to our max recommend cya level of 50 ppm would only take 6.5 total of those sticks. As your cya level rises, the required FC level to remain algae free also goes up. It ends up being a destructive cycle.

See this pool school article: http://www.troublefreepool.com/pool-school/types_chlorine_pool
 
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