What type of hydro set up for 70degree to 80 degree temp in my house

My temp during the summer in the house is set on 74 degrees. If I take it any lower in the summer my bill will shoot up even more. I know for hydro you need the temps to be 70 or below to keep root rot away. What is the best hydro system that can be used if my house temp is around 74-80 degrees durning the summer? I know everybody can not keep there house below 70 all the time too. I know I will be fine in the winter when it is colder and i can lower my heat to 68F. Please help

I have a DWC system, but heard root rot can happen above 70 degrees.

Please help. Does everybody just leave their thermastat in the house below 70f and thats how the keep it cool?