Our Reagent pH test can be used to check the pH of the water ionizer or your tap water to compare to what is coming from your ionizer. The Reagent drops are designed to test the pH of water ONLY!  It is good to occasionally check the pH of the water coming from your ionizer. Our Jupiter ionizers are built to last for many years (usually 10+ is a good average when the unit is maintained properly). All of our Jupiter ionizers come with a FREE Reagent pH test kit.  If you lose yours or run out of your original pH test kit, just order this replacement so that you may have an inexpensive way to continue knowing that your Jupiter ionizer has the pH level that you desire to drink or cook, etc.