The SR Aquaristik COMPACT Reverse Osmosis Systemhas been designed to fulfill the needs of discriminating aquarium hobbyists. The COMPACT reverse osmosis system removes up to 99% of tap water impurities. This is ideal for use in small spaces like under aquarium cabinets or where a traditional reverse osmosis system would not fit. This small compact design still has all the filtration necessary to create 50 gallons per day of pure water. This unit is ideal for making aquarium water safe and contaminant free. Also great for hydroponics.