First of all: Sorry I haven't checked in here lately. I hadn't noticed that this thread had become active again.

While I can't answer the technical side of most of the questions asked (I don't have any insider-knowledge on the Nanofluid) I can announce that I'm planning on doing a long-term test with the Nanofluid. I will use it in my productive system which runs about 18 hours a day. Maybe that will help answer some questions about long-term effects.