What is the best Fuel Additive for the summer?

As the title says i was wondering what most of you guys use for the summer heat. Last year two of our trucks had the diesel form little black balls on the bottom of the fuel tanks and fuel filters which resulted in loss of power. We asked around and a friend told us that it was because the Diesel Carbonized and to use FPPF Total power to not let that happen again. He swore up and down that its the best stuff for the heat and he uses it on his own rig and he's never had issues with the diesel and injectors.

Also the pipes come out between the steps and fuel tanks so there is a lot of heat in that area.