I haven't actually been on here for awhile, but figured I may as well update this. I have decided against an inline pH set-up because it would just be too irritating to maintain. Also, I have abandoned the water bath idea instead opting for going the griddle/steam table pan route. Works great for me. I have, however, finished writing some code for what ended up being a PD controller. Frankly the biggest source of error is the fact that my temperature measurement only comes from one place in the vat. Whenever I stir the pot the reading can jump by as much as 4 degrees Fahrenheit. In spite of that, if I remember to stir regularly enough I can hold the temperature steady within 0.5 degrees Fahrenheit which is way better than any bang-bang controller I have ever purchased in the past. I also have a ramp feature I added in for increasing temperature 1 degree every 3 minutes. Again, due to my measurement only coming from a single point it is not always ideal, but judging by the temperature vs. time graphs I have made with the data I collect with my device I see it is still much better than anything I was doing before. I am tempted to add additional temperature probes and use the average temperature in the pot, but who knows when I will get around to that. Right now I am more interested in giving the device wireless to use a terminal to create a better user interface. I won't ever be selling one of these, but if anyone is feeling like a bit of a maker I would be happy to share much of my code.