Bulk Reef Supply 5 Stage Reverse Osmosis Systems are perfect for chlorine removal, and small amounts of chloramines. Our 5 stage systems use two BRS Universal 1 Micron Carbon Blocks, DOW membranes, and GE Sediment filters. We offer three different levels of systems each providing additional components over the previous. Choose between the Value, Plus, or Plus Water Saver models. We specifically design our RODI systems for use on reef tank and other types of marine aquariums.