so online tubing is like $23857293573495734 but I could just go to homedepo and get the same shit for 5 bucks, does the temperature matter or anything?
just get it from svc or sidewinder, its not that expensive...and i dont think home depo carries laboratory grade tubing, does it? it would probably be too stiff, become discolored, or warped. not worth risking it with a wc loop that could fry your whole rig if it leaks/breaks.
Your coolant of choice can also evaporate through certain tubing materials. I don't lose much at all, maybe 1/4" per month in my tee with 1/2" Clearflex tubing, no evidence of leakage in the 5-6 years I've run this loop. Tygon has a different rate, don't know it off hand.
i use tygon 3603 1/2" ID 11/16" OD, distilled water, and swiftechs hydrx coolant/corrosion inhibitor mixed in. daemas' suggestion of a killcoil is also good!
if you need to make really tight bends, get something softer than what i suggested though. theres no space in my mid tower and after a while, the tightest bend started to kink just a little bit. then again my tubing is fairly thick so that makes it harder for small curves. something to think about...