Hi. I have a pHin and use it now in our outdoor in-ground pool. I don't read or post here much but I'm happy to try to answer any questions. I ordered the unit back in 2015 and it felt like forever for it to actually ship; its worth noting that back then also the Sutro founder was also really nice but I had already given my payment info to the pHin people.
The thing ships with a bunch of chemical powders in bags labeled to be less difficult for people to self-manage their pool chemistry, but at the trade-off of significant use of stabilizers e.g. CYA. In our case, as I travel away sometimes for a week or more, I not only didn't have much time to manage the pool directly, but also wanted some idea of what the pool pH, chlorine and temperature were doing on a relative basis even if not 100% accurate, so I could warn the family not to go in the pool if there were a significant aberration.
The chemical bags are about the size of a CD case and there are also some individually-foil-sealed test strips along with a color calibration card that are sent, presumably for the developers to recalibrate the system overall.
I can guess that not many enthusiasts on this discussion board will like pHin's model of powdered chemical subscriptions. On the other hand, I can guess that there's probably a market for people like me who don't want to think much about the chemical balance, and comfortable enough with potential inaccuracies of using test strips, to want to try a more automated solution that requires less knowledge about the chemistry.
The outstanding question I have is, if pHin is trying to not let perfect be the enemy of the good, is it good enough. My initial thinking is yes. Although I'd love to follow the TFP methods, the testing routine and need to procure and add chlorine are still surprisingly time consuming relative to pHin's continuous monitoring & pouch-based approach.
