My system was having troubles keeping my North bridge & CPU Temps cool on idle (~75C and 55C, respectively...) and I wanted to figure out the problem. It turns out my 3 fans below my Thermochill 120.3 were all "gunked up" and would not spin fast or even at all.
So since it had been ~1.5 since installing the water loop, I tore it all down to clean up all the gunk that had been forming on the side of the tubing, as well as cleaning on the radiator. This also gave me a chance to order 3 new Razer fans that will hopefully not go bad like the 3 Yate Loons previously had.
My question is, can I stop this gunk from building up inside the system? It is a thin layer of whitish film that was lining all the tubes. I put PT Nuke in Distilled Water in my loop, and continued to change the water out every ~4 months, but is this still natural?