The invention relates to purifying unwanted moderately saline water. The methods of the present invention including passing moderately saline water through an ion exchange media saturated with ammonium salts to produce fertilizer water. In addition, the present invention relates to a method of passing moderately saline water through a dual bed cation and anion exchange process for producing purified water. The first cation exchange media is saturated with acids of hydrochloric, nitric or sulfuric acids. Meanwhile, the second ion exchange media is saturated with ammonium hydroxide. Passing the moderately saline water through the first ion exchange media creates an acid rich water which is then passed through the second ion exchange media to remove chloride, sulfate, nitrate, and nitrite anions. Through a regenerative cycle, a fertilizer water is produced which is rich in ammonium chloride, ammonium nitrate or ammonium sulfate.