Have been working with Sutro support (when they care to respond) over the last 30 days, trying to get the newest cartridge to work. Have had to take photos and answer all kinds of questions, do all kinds of tests for them off and on for weeks. Ultimately, no go.
Now trying to get a refund on this device and cancellation of service, they're trying to tell me I'm out of the refund window but they'll be nice enough to give me a free month. (THE DEVICE DOESN'T FREAKING WORK ANYMORE!) Their warranty is for 1 year so I should be covered, but I don't even want to continue using this POS.
UPDATE: TWO MONTHS LATER, still fighting with them about the issue. They are now asking me to try a fifth cartridge in a row. I’m sure this new cartridge will work where the previous 4 did not. Yes, it’s definitely not the unit itself! Morons
Even in the preceding 11 months, it was routinely a pain in the butt to get it to pair, get it to accept a new cartridge, and so on. And the value just isn't there on a spa. Pretty sure I can remember toss in 1/4 c of Ph Up every few days? Now I know...