If you are drinking and immediately peeing, a very likely possibility is an electrolyte deficiency. I understand that increased urination is also may be an attribute of altitude acclimatization. But if you are drinking and the water is going right through you, you might consider upping the electrolytes. (Note: diamox is a diuretic, so in theory, it may increase urination). Obviously things to discuss with your doctor.
Good luck on Kili and I hope you tell us about it. Kili is on my list too, maybe for January or February 2012.
