That is the question. I've been keeping an eye on them and hopefully we'll get some reviews on them. There's a single review on BRS, nothing on Amazon or Marine Depot. It looks like a really good deal for $60 and I'd like to try one. Frankly, I'm waiting for a few reviews before I pull the trigger. I believe our very own @anit77 uses a dosing pump that is the same brand and he likes it just fine. I don't know anyone who actually owns one of these units though.
The app is pretty easy to use. The only thing odd about is that it has a Chinese character to denote minutes on the time remaining. I have been testing the alk every few days and it is holding steady at 8.5 +- 0.1. Marine Depot has a video that shows the setup of both the device and app.
That's a fair point. Having never used one before, I don't have anything to compare it to. If I had a tank in my bedroom, I wouldn't want it dosing at night, or long frequent doses. In my case, the tanks are in my home office and dosing a tiny bit every three hours for 1-2 seconds.
Coral Box also makes one in this price range with a WiFi connection.