NOTE TO VIEWERS REGARDING PHIN
In 2018, I stopped using PHIN and cancelled my subscription. I had issues with the pH accuracy; the unit kept telling me to add pH Up even though the level was too high. Also, their customer service and support severely declined since the company was acquired by Hayward. I still love Hayward products and use a lot of them with my pool, just not pHin.
Please watch this video for complete details: