Aquarium Reverse Osmosis D ionizationRO and RO/DI systems to help remove impurities from your water such as, chlorine, phosphates, heavy metals and more. All of our systems remove 99% of organics from your city water. We recommend you always use RO/DI water on any of your aquariums, saltwater or freshwater. Using these systems will keep you free of unwanted nutrients and algae growth. Your fish and corals will thank you for it. We recommend the AquaFX Engineering Ro/DI Units, these are quality built in the USA RO/DI Units. We offer units that will produce up to 6000 gallons per day!