Now look , THIS is a good idea [big grin] [up]
I've been thinking about this for a while and I'm really starting to think it's something that can be done. The Radioactive Slime and Lava effects both emit light and are visible at night and these effects are just made to look like thicker liquids. Rather than changing the physics of the way light reflects off of water jets I think a good solution would be to add "Colourable Water Jets" as a separate object that works in a similar way to Lava and Slime.
Bear in mind I know nothing about making effects in games but as we already have two liquid like effects that can be seen at night I really think this is something we could see.