Can I use the Pool Calculator to calculate pool volume?

[Nightmare]

I never had been able to get a "good" number for the volume of my pool. The PB came up with 1 number, I used an online calculator and it came up with another number.

I've been doing most of the chemical balance based on 25,000 Gal. And most of the time it works out fine.

I had a very low FC level today, so I brought it up to shock levels. Here are the steps:

Basic Chlorine test was barely yellow.

Add about 1.5 Gallons of HASA 12%

FC tested at 6.5 about 3 hours later -> HASA Liquidator was running as normal

Added 1 gallon of HASA 12%

FC tested at 16.5 about 3 hours later -> HASA Liquidator was running as normal

If I use the final FC and the Middle FC and reverse the calculation on the Pool Calculator to 1 Gallon I get a volume of 12,500 Gallons of water.

I don't see how this is possible.

What am I missing?

 

[linen]

There is a location near the bottom of the poolcalculator.com that does estimate pool volume but it is limit to round, rectangular, and oval pools. If you want, you can post some dimensions of your pool along with a picture or drawing and we can help estimate.

What am I missing?

I am not entirely sure, but it does sound like you are fighting something in your water. I would turn off the liquidator tonight, bring the pool up to your shock level and do a OCLT (http://www.troublefreepool.com/pool-school/overnight_fc_test).

 

[JasonLion]

There are way too many unknowns in the situation you describe. The Liquidator is adding chlorine the entire time, the initial test was not a FAS-DPD test, too much time passed between tests, bleach strength varies a fair bit from the listed strength sometimes, and any sunlight on the pool during that period would have completely thrown things off.

It is possible to get a sense of the size of the pool from measuring before and after chemical additions, but even under ideal conditions this isn't a very precise procedure. The best thing to do is to watch and see if many different chemical additions are consistently off in one direction or another, rather than depending on a single instance.

 

[anonapersona]

I think you can use pH and TA to back into a volume if you are pretty accurate with the TA. At least, over time, by observing pH reaction to adding acid when TA is known, you can get a clue if your volume is a bit high or a bit low and tweak your numbers that way.