lol. Well said, Midknight.
I did find this: If you use larger diameter tubing, you need more of it. If you double the diameter of your tubing (say, use 1/2" instead of 1/4"), you need three times the length of tubing. I think the idea is that, the more water you want to process, the thicker the tubing you want (which, according to above, also means a greater length of tubing). The fellow on RC who seemed to know what he was talking about recommended about 75' of 1/4" ID tubing for a 75G tank max. I didn't find any special formula to calculate any of this, though!
Also, when you're cycling the unit, you need to adjust the drip rate accordingly. This, copied from an RC thread, in relation to the diameter of tubing and their corresponding drip rates:
for .170 it should be less than 1 to start with
for .250 it should be just over 1 to start with
for .375 it should be just over 1.5 to start with.
for .5 it should be in the 2~3 to start with
These are ESTIMATES, you have to test the output regularly to adjust the flow rate.