Piping and Barbs for external Connections
 

OK, I've been staring at all of the plumbing parts at Home Hardware and Canadian Tire and I can't figure out for the life of me which parts to use to make a 1/2 " hose connection between my computer and a cooling box.

I'm more than happy to use platics barbs (less metal the better as far as I can tell) since I haven't seen any advantage to using metal except looks or soldering capability.

Also, assuming I'm using all copper core, copper pipe, plastic, and copper/brass rad, what is the least toxic coolant I can use for an extended period of time? I hate the idea of my kid sneaking in, spilling antifreeze and playing with it.

Also, is it worth putting a T junction for draining the system? Any suggestions for the valve type?

Thanks,