Drain line size question...

I'm currently installing a Fleck 7000SXT 3.0 cubic foot system in a 14x65" tank. The DLFC button says 500 (I assume that's 5.0 gpm). Should I use 1/2" tubing or 3/4" for the drain line, or does it even matter? Not sure if this will makes a difference, but I need to run the drain line overhead for about 50' as well.

Also, since I'm running the line overhead, is there anything special I need to do? Can I run it straight up from the valve, or should I drop the line down first before going up (kinda like a p-trap). Might be a dumb question, but as you can probably tell I know little about plumbing (I'm learning fast though!).

Thanks!

Consdiering the length, code, etc, run the drain line in 3/4" PVC. it is cheap, simple, quick, etc. The main concern about the drain line is to not run it to far down, or too far up. To far across... not a problem. No more than 10' high without consulting us on how to do it, not more than 10' below the softener without a vacuum break.

Thanks Dittohead! That's exactly what I needed to know. It's 9' up, so shouldn't be a problem. I didn't even think to use pvc - that'll save me some $$!