More Liquid Chlorine Needed than Advertised?

[sigmond]

Pool specs: 10,600 gal (at least on paper), FC = 4.13, TC = 4.25, PH = 7.7, TA = 62, CH = 251, TEMP = 87

It is taking 20oz of LC (10%) to raise the level 1 PPM. The bottle says it should take 13oz to do so. So ... my math tells me that is should take 13.78oz (for my pool) to raise the PPM 1. I am thinking that either my pool is bigger than what they have on paper - or the chlorine sucks.

What do you guys think?

 

[JoyfulNoise]

Or … your ColorQ (or whatever digital tester you are using) is giving you erroneous results …

Pools rarely ever match up with their design volumes. My pool builder said my pool was 15,000 gallons on paper. Nope. I chemically measured it and it was a little over 16,500. That matched up with testing. You probably need to change your volume until it matches your testing … but … you need to get rid of the digital tester. They are often wrong or, worse, they will get less accurate with age and you’ll be dealing with a moving target.

 

[Sunnydaze]

Another potential factor could be degraded liquid chlorine. Check the date of yours. It should be printed on the bottle in Julian date format such as "21189" which would be the 189th day of 2021 or July 8th. Fresher is better and make sure it's not stored in the sun and/or heat both before and after you purchase.

 

[sigmond]

The ColorQ has been very accurate & consistent. I had discovered early on, the secret is to calibrate each tube for each measurement. I suspect because each tube may discolor differently over time. The Lamotte manual says to only calibrate the first tube. Also ... I have a Taylor Kit K2005 that I use to double check once a month.

Maybe, Kevin is correct - and my LC may be too old. It also sits in my garage, which can get hot.

Q: Is there any way I can accurately measure the volume of my pool?

 

[YippeeSkippy]

The ColorQ is renowned for bad calcium hardness testing.

www.tftestkits.net can hook you up with a better calcium test.