I always wonder, why this is not a problem in Grand Canyon? The toilettes at one and half mile, three mile, Indian Gardens, Cotton wood CG and BA CG are all working fine and probably with more traffic than on Mt. Whitney - the ranger said roughly 10000 people go into the canyon every year! So just go back to keeping one next to the hut (as it used to be in 1992), one at Trail camp and one at Outpost camp.

Personally, immodium works fine for me!