Sudden Chlorine Loss

[ChiefRob]

All season long so far I have had an easy time with chlorine management. Test twice a day religiously. Add about a gallon of 10% chlorinating liquid a day. Water is spectacular, have no issues and pass an overnight free chlorine test. Suddenly I am seeing my numbers go down quickly during the day. If I add two gallons of bleach or 10% chlorinating liquid I will see numbers dwindle over the course of the day. My CYA was low at the beginning of the season so I raised it to 40. Just tested it again and it’s below 20. That would explain my chlorine loss correct? Real question is would the two or three times I have had to add water from evaporation this year dump my CYA that much or am I missing something? I will boost my CYA back up thinking that will eleviate the issue. Thought my experts?

 

[jblizzle]

CYA is not lost to evaporation.
It is lost from splashout, backwashing, etc. It can also break down slowly, but usually only 5ppm a month of so.
The other possibility is a leak that is causing you to lose water.

 

[Texas Splash]

Evaporation wouldn't lower your CYA, only water exchange does that. It's possible some of it simply degraded each month which is common. Some brands, for whatever reason, have been a bit unpredictable and dropped faster than others. I had that happen to me once. So the lack of CYA could explain the drop in FC. Hopefully you caught it in time to where you can simply increase the CYA and press-on. If after increasing the CYA you find the FC still dropping, you may want to do another Overnight Chlorine Loss Test.

 

[Jimrahbe]

Rob,

Sounds like two things happened at once.... Summer came and your CYA got diluted by water additions...

I suspect bumping your CYA back up to 40 is going to fix your problem...

Thanks,

Jim R.

 

[ChiefRob]

Thank you all for the quick replies. I will bump up my cya and report back in a few days.