xbitlabs indicates a 6800 is nearer 40watts
http://www.xbitlabs.com/articles/vid...v-power_4.html
I would think that it is far more helpful to calculate the prsure drop by analyitcal methods. I would of thought that the big water is a maze type block with loads of turns. I'll have a look at it this evening.
The 1/4 inch tube is going to make a huge difference isn't? Espeically the borda head loss in the y splittler.