how big is my pool?

[EmilyOTR]

I've always used the 12,000-15,000 gallon estimate because it's what the pool store guys told me (they open and close for me) and when I've posted various things here, some of you agreed. Today I did a FC test, I was at 5.5 FC. I used 15,000 gallons in pool math and added 69 oz chlorine to reach 10 FC. 15 min later (also very cloudy day) I'm at 10.5. So, 15,000 is pretty close, but I'm not good with this kind of thing, can someone tell me closer what it is? Since it was higher am I more like 14,000?

 

[Newdude]

Since it was higher am I more like 14,000?

Maybe. I just did some maths before for a 15k ish pool and their 392 sq ft perimeter meant that the normal +/- 2 inch fluctuation was a 996 gallon difference. You can be up or down 500 gallons from perfect at any time due to rain/evap.

You were over by .5 and that's about as close as you'll ever be. The pool is 15.k gallons and the test is a monentary snapshot of that 1/200th (?) of a gallon over there. A minute later its a different bit of water that came from a different over there.

The test itself may be off by .5, as well.

I like to say the 'point X' is irrelevant. The 10 is the important # to me, and you are well above minimum. If it's a .2 or a .5, I'll high five you either way. If it's a 3.5, I again do not care about the .5. You need several PPM and STAT.

 

[ajw22]

What % chlorine did you use?

And since you don't really know what actual % chlorine you added versus what the bottle claimed you don't know if the variance is due to the chlorine % or your pool volume.

There is also a Chemical Way of Calculating Pool Volume using an alkalinity test kit, sodium bicarbonate or acid, and the formula.

 

[EmilyOTR]

What % chlorine did you use?

And since you don't really know what actual % chlorine you added versus what the bottle claimed you don't know if the variance is due to the chlorine % or your pool volume.

There is also a Chemical Way of Calculating Pool Volume using an alkalinity test kit, sodium bicarbonate or acid, and the formula.

12.5%

 

[EmilyOTR]

Maybe. I just did some maths before for a 15k ish pool and their 392 sq ft perimeter meant that the normal +/- 2 inch fluctuation was a 996 gallon difference. You can be up or down 500 gallons from perfect at any time due to rain/evap.

You were over by .5 and that's about as close as you'll ever be. The pool is 15.k gallons and the test is a monentary snapshot of that 1/200th (?) of a gallon over there. A minute later its a different bit of water that came from a different over there.

The test itself may be off by .5, as well.

I like to say the 'point X' is irrelevant. The 10 is the important # to me, and you are well above minimum. If it's a .2 or a .5, I'll high five you either way. If it's a 3.5, I again do not care about the .5. You need several PPM and STAT.

good point, and my water level is kind of low right now too, so maybe right at 15K? is my head doing this correctly? lol

 

[Newdude]

Is my head doing this correctly?

Exactly right. You were 500 off with your guess. Evap added another 500+ off and boom. You overshot the 10. Overshoot anytime. It's a GREAT problem to have.