i appreciate all of you who have contributed to the discussion and i say many thanks to you...

the issue arose during a 22 mile r.t. hike that gained 4,100' in 11 miles w/the last 1,000' summiting in the last mile scrambling over rocks and brush. temps rose into the mid to upper 80s, zero shade, and 'fire danger' humidity. that's typical where i day hike - in the los padres forest in southern california.

not only volume depleted - and as arney pointed out - electrolyte depleted as well - which exhibited on the summit as a 3+ muscle cramp in my inner thigh - felt like it was gripped by a lion..

as suggested, and after further research, purchased gookinaid (hydralyte in the us and aquaforce down under) as it seems to have the right stuff. has subtle flavor. will post further after field testing.

thanks again,
bsmith