Thanks to Meg, I received my new (correct) CYA test tube.
My question is: Putting in drops at waist level until the black dot goes gray or is completely disappears?
SWG pool at 13,000 gallons and 2 LBS of dry Cyanuric acid via the "sock in the skimmer" method (so far)
Just need a clarification (excuse the pun) on the dot
thank you in advance.