Using hypochlorite dilution to measure pool volume

[cschnurr]

Interesting discussion. I kept track of the water meter during the first fill.

Since Chlorine % is based at the time of manufacture and decreases during shipment/storage, I don't think it is a good starting point from which to determine your pool volume.

If your pH drifts considerable, you could wait until it gets to one extreme, and see how much Muriatic Acid it requires to get to the opposite extreme. Or similiar with CYA.

If you have an SWG, do the same with ppm of salt.

If at next years opening significant adjustments are required, you may get better results.

Also don't forget that depending you your test kit, the measurements themselves are not exact values.

[cleancloths]

Don't know if your pool is a constant depth, or is sloped so please bear with me. Why not take a water meter reading (and make sure no water is being used in the house) and then measure the level in the pool - now add exactly 2" of water to the pool, then go read the water meter. (2" is an arbitrary number - you pick what you want to do.) This information will tell you how many gallons per inch to your pool. If the bottom is sloped you can use basic trig to figure its realative size. I think this method will be far more accurate than using titration results with reagents that are not of exact concentrations.

For instance I know that my pool is almost exactly 500 gallons to the inch.

[waste]

Framcus, welcome to the forum! Your and Richard's discussion went a little over my head, but I'll try to offer some practical advice
Since the shape of the pool (and it's bottom) precludes a 'plug and chug' number, do what we pool dudes have been doing since the first pool was built - guestimate. Run the numbers with your best guess as to depths and areas and get a good approximation of the gallonage, then use 'trial and error' to make chem adjustments (and follow the first rule of pool dosing: "add less than what you think you need" - you can always add more to get where you want). Also, please keep in mind that there is a fairly forgiving range of 'acceptable (optimal) levels' for the various parameters of pool chemistry - use your guestimate as a starting point and, through keeping a journal, adjust the suspected gallonage accordingly.
While it would be more satisfying to KNOW the exact gallonage of the pool, sometimes you just need to be satisfied in knowing that 5 lbs of baking soda will raise your total alk 10 ppm. Don't loose track of the fact that the end result; having water that is clear, sanitary, not gonna hurt the pool nor equipment and a swimmable, hastle-free pool, is what's really important!!
Again, welcome to the forum - I suspect that you'll be a great source of knowledge, though I shudder to think about the headache I'll get if you, Richard, Evan, Steven, Pat, Michael & the rest all post on one thread