Active Aqua Chiller with Power Boost, 1/2 HPDescription Environmentally Friendly Chillers: Active Aqua's chillers are not only ideal for maintaining the optimal temperature in your reservoir's nutrient solution but also environmentally friendly, using R134a refrigerant. The user friendly temperature system lets you manage your desired temperature range as needed. Plus, all models now come with a boost function for faster chilling and quicker establishment of the initial nutrient solution