yeah, the reserator series is the best silent cooling answer possible. Even if you manage to kill a pump, the pumps are built by Eheim, the best brand for them, and can be easily swapped out for an eternity of cooling.
I might do something freaky and get a 2nd tower for my gfx card when i buy my r600. I have to check with zalman if the new res2 radiator style is sufficient to cool the new r600 vid card from ati (the 65nm process version, NOT the 80nm)
they are really nice as far as customer assistance.
On the topic of coolant additive: Yes, I use only steam distilled from the supermarket (normally poland spring, seems to work fine) and a good pour of water wetter from Redline.
Yes, as well I recommend adding a couple of ounces of water wetter to your zalman blue liquid+ steam distilled water. WWetter can be used without other coolants like I have it, but it also enhances cooling systems in less quantities as an additive. So... why not is what I say.
my system is now going past the 2 year marker almost never turned off and its dead silent. I know for a fact that either its a miracle, cherry picked luck of the draw pump or the WW is actually doing what it is supposed to: completely prevent corrosion and giving a good lubrication. It also breaks the surface tension so the pump has a lil less resistance I am guessing. shrugs