Active Aqua Chiller with Power Boost, 1 HPProduct Details Active Aquas chillers are environmentally friendly (they use R134a refrigerant) and are ideal for keeping the nutrient solution in your reservoir at the perfect temperature. Each unit has a user friendly temperature system that allows you to control your desired temperature range as needed, and all models now have a boost function that accelerates the chilling process for quicker establishment of initial nutrient solution temperature.