This is a testing liquid for the measurement of pH level using the Titration (drops) method. Maintaining your hot tub at the correct pH level keeps your water clear, free of bacteria and helps extend the life of your hot tub equipment. The correct Ph Level is between 7.2 and 7.8. Phenol Red is used in the Beachcomber's chlorine and bromine test kits.
To properly titrate (apply drops) while testing, reagent bottles need to be fully vertical during titration to ensure that the correct drop is produced.