There is nothing in a chargecooler system that needs to be treated any differently to a normal cooling system. I use a standard Glycol-based coolant in my predominantly aluminium system, purely to stop it freezing in sub-zero temps.
You need phosphated OAT. Avoid straight water or it will result in the system corroding. The phosphated OAT is compatible with the metals & fluxes in the system and provide better protection than straight OAT coolants.