Chlorine from dosing tank

A_kraker99

Well-known member
Jul 18, 2015
103
Zeeland MI
I had another post with concerns that my daily chlorine usage seems way too high, but I guess I may just be at the high end of normal based on responses to that post. To maintain my levels I have to add about 4 PPM per day.
That got me thinking. I have a pentair dosing tank that is somewhat translucent plastic that sits in the sun half of the day. Is it possible that the sunlight is reducing the effectiveness of my 12.5% chlorine as it sits throughout the week?
 

Richard320

TFP Expert
LifeTime Supporter
Jan 6, 2010
23,873
San Dimas, CA (LA County)
Good call. UV light is the enemy of bleach.


I figure your 12.5% stuff will be a little above the green line. But that's full sun, and yours blocks some. A couple years ago there was a thread where the guy actually buried his tank to keep it cool and he put a cover over it to block the sun.
 

Brett S

Well-known member
Mar 15, 2019
647
Orlando
I keep staring at it, but I do not understand that graph at all. The bottom axis is ppm CYA and as near as I can tell it’s showing that the higher the CYA level the more chlorine is lost to UV per hour. But I thought that the whole point of CYA was to slow chlorine loss from UV. What am I missing here?
 
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Richard320

TFP Expert
LifeTime Supporter
Jan 6, 2010
23,873
San Dimas, CA (LA County)
I keep staring at it, but I do not understand that graph at all. The bottom axis is ppm CYA and as near as I can tell it’s showing that the higher the CYA level the more chlorine is lost to UV per hour. But I thought that the whole point of CYA was to slow chlorine loss from UV. What am I missing here?
I must agree with you. I seldom use that graph, so I never noticed before, but I think it's labelled wrong. Maybe you can make more sense from the text. It's in this thread Pool Water Chemistry