I ran across this recipe a couple of years back, and will never go back to buying premade electrolytes again. It works awesome, is cheap, is extremely easy to make, and most of the ingredients come out of your kitchen.

In a two litre pop bottle mix:

2 Tsp Baking Soda

2 Tsp Salt

60 cc of Battle

15 cc of Dextrose

Mix all ingredients together in a two litre pop bottle along with warm water. Be sure to shake the bottle before you pour it into the tubing bag, and serve. 

Battle can be found at most Vetrinary Clinics at around $15 to $20 for a smaller bottle, and the Dextrose is around $5 a bottle. Compared to the average price of a bag of premade electrolytes, the homemeade ingredients last longer and cost less. Give it a try and let me know, i have had great success and would like to hear what you think. 

KR