Is there a chemical that you can add to the ice at an ice rink to make
the ice glow under blacklights?

Here's a product that may interest you:

http://www.jetice.com/products/hockey/ice_paint/black_light_ice_paint.html

how about antifreeze :D
or laundry whitener , 
tonic water

Or u could get a cat to piss on it  :D

http://riskreactor.com/Fluorescent_Tracers/Fluorescent_Tracers_Main.htm

"5. BULK FLUORESCENCE TRACERS.

The detection and measurement of seepage of liquids, such as water in
soil irrigation, may be accomplished by use of ?bulk fluorescence?
effects. This is where thick layers or bulk quantities or
tracer-tagged liquid are observed., as contrasted with the detection
of fluorescence in thin films. Also included in this category are high
visibility fluorescent tracers, which are used as sea or snow markers
for indicating locations. Locations such as a snowed-in airport
runways, skiers, survival usage, and locating flyers down at sea are
just some examples."

fine lint will work. like from your dryer.