Lifehacker's guide says that colored coolants gunk up the loop. This is on an xspc raystorm 750 rx240. How much of a problem is it? Is it not something that can be addressed by flushing the tubes and toothbrushing the reservoir or are we talking mildew stubbornness here? And does adding coolant render any significant advantages? How many degrees celcius different are we talking about, or will it make the rad fans run quieter?