I should think that you would get an increase in accuracy by putting the controllers in separate enclosures. But uf you want them in the PC fine. Nothing stops that. If you put it inside the PC however then you might condider simply purchasing a general purpose data acquisition board (ISA or PCI) that has A/D inputs and a digital output port to control the water flow and fans. Relatively straight forward PC based software could then control the temps still leaving much of the PC horse power left to other functions. This would be especially true if the PC was running a multi-tasling OS such as Win2K.

Michael Karas