I don't think using it to tell a doser when to turn on or off will be a real benefit. You can split up your doses to multiple times per day to keep your system rock solid using a co troller or programable timer;, or use a reactor.
It might even lead to over dosing and swings. When I was testing every day to get my dose dialed in, it seemed that there was a full 2 day lag time between an increased dose and it showing up in the test.
The peace of mind this would give me when I am out of town would be priceless. When I am in town I can generally tell if a parameter is starting to go off by how certain corals look. I will definately be getting one as soon as they roll out.