I know ppl hate vinyl tubing...
 

But would it be good for the "airtrap" in an inline system's T? I have silicon tubing, but it's so opaque that it's very hard to see where the water line is. Tygon is way too expensive to even consider using (for me)... will the vinyl conform OK to the T? I guess collapsing isn't a problem either since it won't be making any bends. Or would the reinforced vinyl be better?

Thanks in advance!

i dont see why vinyl wouldnt work for that part of the system as long as there are no tight bends (which really isnt a problem anyways since you can heat and shape vinyl tubing). id use rugular vinyl; it would be easier to see thru than braided.

Even if it does kink somewhere, does it matter for a fill tube? I squeezed my fill tube through a tiny hole between my case and PSU to get into the upper section of my case, cut the inside diameter of the tubing to almost nothing through that small area. But what is the maximum flow rate you need from the top of the fill tube (I think of it as my mini-rez) into the rest of your system? During the process of filling the system you can move the tube around so it's straight, and once the system is full, if you have that much liquid moving from the fill tube into the coolant-loop, you've got bigger problems than a kinked hose to worry about.

I used it like that for some time. It will be fine, however it does tend to harden with age, so make sure you clamp it tight.