Did I just measure my pool volume by comparing before/after chlorine levels?

I am lazy and don't want to measure my new pool. It's an odd twisted peanut shape. Maybe I would like to measure it but I don't really know how. So I took the chlorine level before and after adding a known quantity and fiddled with the "gallons" value over at poolcalculator.com until its recommendation matched reality.

I added 121 oz of 8.25% bleach to my 3.5ppm and ended up with 10.5ppm. Apparently that works perfectly on an 11,500 gallon pool. Absolutely precisely in line with the measurements and additions.

Did I accurately measure my pool water volume? Or is there some gotcha that makes that invalid?

I just bought this house. We closed a little faster than we thought and now I'm trying to get a handle on this pool. The CYA is stupidly high, so the ~10ppm is probably where I want to be for now anyways. (I think)

I kind of just dumped the first jug of bleach in to see what would happen. Until now the previous owner had been paying someone a lot of money every month to, from what I can tell, let the CYA run out of control. It's more than 100 but less than 200 I think. I am going to try the dilution test tomorrow. We are in the middle of a mandatory water conservation order, so I don't plan on any partial draining.

I think you are close on your volume.

Odd shaped pools can be measured as follows:

1. Note the reading on your water meter. (If you don't have a meter, disregard this post)
2. Fill the pool so as to add exactly one inch of water.
3. Note the reading on your water meter after filling.
4. Subtract the first reading from the second. This is the number of gallons of water to fill your pool one inch.
5. Multiple the result in step 4 by 12. This is the number of gallons of water to fill your pool one foot.
6. Multiply the result from step 5 by the average depth (in feet) of the pool. Voila you have your volume

Determine average depth by measuring the depth at the shallow end, add the depth at the deep end and divide by 2. You can get more accurate by measuring the depth along the centerline of the pool (lengthwise) every 1, 2, 3 feet (depending how accurate you want to get). Add all the measurements then divide by the number of measurements.

Try to eliminate other household uses of water while filling.

If you can (or need to) fill multiple inches, it will be more accurate. In other words if you fill two inches, multiply by 6 to get gallons to fill one foot. Three inches, multiply by 4, etc.

Adjust for other features like steps, radius of bottoms corners, etc. by estimating the volume (in square feet) of the feature and multiply by 7.48 to get gallons then subtract from the total gallons from step 6.

The only real way to know for sure - exactly - is to empty and refill through a meter. S-)

WHEEW! :tired:

Like Watermom says, you're probably close enough. Pretty soon you will know what happens in YOUR pool when you add so much of this or that. That's all that really matters.