You might want to try Endurolytes from Hammer Nutrition. If I'm about to do a "hot" (95 - 100+ F) ride, I'll take one perhaps 15 minutes before I start the ride. Also, with the heat we've been experiencing lately, I've switched from two bottles of Gatorade on the bike to one water and one gatorade. For longer rides in the heat, I down an Endurolyte about every 15 miles or so.