CYA testing with Pentair test kit

[Pool3519]

Moved from here.
Hi, Im new here and have a dumb question on this test. I am using the Pentair Rainbow CYA test and I have received conflicting info. I have filled the tube with pool water and then the reagent. Then stirred it up with the dipstick. Am I supposed to pull the dipstick up from the bottom and pull the reading when the black dot appears or pull the dipstick all the way out and lower it until the black disappears. The two methods give a much different reading (50ppm difference). The test strips line up closer the the latter option. I appreciate any help!

 

[mknauss]

Welcome to the forum!
@Jimrahbe has experience with that type of CYA tester. Let's get his guidance on your question.
I suggest you read ABC's of Pool Water Chemistry.

 

[Jimrahbe]

P,

You raise the dot to the top and then slowly lower it until the dot just disappears.. I usually like to get the dot to "almost" disappear. Stopping when you really have to look for it works best for me.

Thanks,

Jim R.

 

[Pool3519]

Thank you sir