Thank you & Question on CYA

May 11, 2014
15
Malvern, PA
I got my pool installed in 2011. The installer got me started on a mineral system. (They do not like chlorine). It was a miserable first 2 years. Algae blooms, constant brushing and cleaning. Hated it. Tried Phos Free. That was worse. Clogged up my filter and had to do a complete clean out. Talked to the installer before opening this year to see what I could do to fix my problems and they say they were no longer using the mineral system but switching to Pristine Blue. He suggested I read up on it first then get my kit from them.

I did my research and found this site through the course of it. Best thing I ever found! Got the test kit and I opened my pool using the method described here. I cannot thank you guys enough. My pool has been practically zero maintenance this year. No algae at all. Just clear blue perfect water. I typically add about 32oz of chlorine daily. On really hot days and lots of swimming I add about 48oz daily. I lose about 2 ppm of chlorine a day. Now for the questions...

My current numbers:
FC 3.5 (Its normally low in the morning before I add my chlorine for the day)
CC < .5 (barely turned pinkish. One drop of reagent brought it back to clear)
PH 7.6
TA 70
CH 200
CYA 55


Since opening in May, my numbers have been rock solid every time I test. They stay in sync with the recommendations from Pool Math. I test in the morning everyday before adding my chlorine. I normally get the following:

FC 3.5 - 5.5 It all depends on hot & sunny or cloudy and raining.
CC 0 - .5
PH 7.6
TA 60
CH 200
CYA 40

The last two weeks my CYA has jumped from 40 up to 55. My TA went from 60 to 70. I don't get why these numbers are going higher. I have been getting liquid chlorine from Leslie's Pools since May. Its 12.5%. The label does not state it has any stabilizer in it. I do not use any pucks. I have not added anything to the pool but the liquid chlorine. The only difference is that I ran out of reagents for the CYA testing and ordered more from here. I have been using the new reagents the last few weeks. Any thoughts as to why my numbers would be changing?

Thanks. Love my pool this year!!!!
 
Both of those results are within the precision of the test, CYA is +-15 and TA is +-10. Different batches of reagent sometimes give slightly different test results like that, especially if your old reagents were getting old.
 
Welcome to TFP!

You are correct, the CYA can not go up on its own. Being a subjective test, I would guess testing error. Make sure you the correct lighting and you can pour the sample back and forth a few times to average out the reading.
 
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