One cubic foot of nitrate selective anion resin will remove 840,000 mg/l (or parts per million - ppm) of nitrates. As an example, if you had 50 mg/l of nitrates in your water supply, divide that into 840,000 and you could achieve 16,800 gallons of water per cubic foot of media per regeneration using 10 pounds of salt per cubic foot. Other factors include sulfates in the water source. If the ratio of sulfates to nitrates exceeds a 6 to 1 ratio, then this will greatly reduce the amount of throughput between regenerations. Another factor is contact time. Flow rates of four gallons per minute (gpm) per cubic foot (cf) or less will allow for maximum removal percentages. All of our systems include an upper basket so that the anion resin will not wash out in the backwash cycle. A nitrate system should be installed downstream of any filter or water softener and is not intended for any other purpose. The water must have any iron, sulfur, manganese or sediments removed ahead of it. A nitrate reduction system will lower the pH of the water.