Looking For Info On Water Dyes

Hello All

I am thinking about building a new watercooled computer and plan on putting a window in the case , lighting the interior with a small neon blacklight or two.
Anybody know of a water dye that changes color as the water temperature changes in the range of 20-90’C?
Bonus points for dyes that don’t eat plastic or copper or screw up the thermal conductivity too much.

Liquid crystals might do what you want. See http://www.edmundoptics.com/IOD/DisplayProduct.cfm?Productid=1642 The link is for sheets of the stuff, but you can also buy the material in bulk. It’s pricey.
You might also consider Kalliroscope fluid. There are lots of different recipes for the stuff. It won’t change from pink to blue, but will reveal changes in the heat dissipation pathways by changing its reflectivity.