Ah yes, forgot, I added an aquarium pump also, that is probably the best mod to do. Adding a pid controller requires a bit of hacking.
This shows my pid controller and where I stuck my pump,
I got a wild hair to modify my CPE2 Plus. Not that it was terrible but the mechanical thermostat would dwell a couple to few degrees. I decide to try and shoehorn a digital temperature controller into it. I had to think about it a bit because it it a one way ride. After collecting all the bits...
I've since replaced it with this one,
I had to add a 12V power supply to make it work.
Is it worth it?????? I just like being able to set the temperature I want and be done with it. There is a one time calibration to do ( set the offset ).