I just ordered $100.00 lbs of Maltrin QD 580. It cost me $57.00/50lb bag and I had to buy two of them from ET. Horn Company. They have a distribution warehouse here in Salt Lake City and will ship it here with no freight charges. I was told by the salesman at ET. Horn that they sell literally tons of this stuff to individual cyclist. I plan on continuing to get my electrolytes in my body via Thermo Tabs (salt pills) and a magnesium/calcium pill that I have always used. I am one of those riders who really losses electrolytes (caked in salt after big hot rides). Maltin is pure carbohydrates so you still have to get proteins, electrolytes and whatever your body seems to want on rides.
I have been investigating the theory of isotonic solutions so I will not over mix my solution and have gastrointestinal problems.
I looks like if I use 1/2 cup of the stuff per bottle that will give me 150 calories. I try to drink 3 bottles/hour when I ride when its real hot so there is 450 calories, leaving me deficit around 150 calories at a moderate to hard effort, which I usually make up for by eating while riding.
I will let you know.