Yea it really is hit and miss with the Fesser 1. I think it may have something to do with the pumps impeller design. Then again I could be completely wrong. I have some pretty cool nano silver fluid to test out in it soon. When I drain this loop I am going to try and have a friend take some pics of the "gunk" under a microscope.
SXR, I ran my TT kit for 5 months with out a single problem and its been in my server ever since running 24/7 with out a problem.