The red flow wheel below measures coolant flow and sends an RPM signal to the CPU fan header. It uses the LED's to measure RPM. If the coolant pump stops the system will shut down automatically. =)
Don't get me wrong the Thermalright NB-1C is the mother of all NB air coolers, but here...
It should be known that de-ionized fluid has a natural tendency to re-ionize itself. In other words if you submerge two dissimilar metals in a solution that has been de-ionized, galvanic corrosion will quickly take place.
For those of you who are using all copper water blocks with aluminum...