Hot Tub & Swimming Pool Pre-Filter (Turbo Ion Exchange Pre-Filter) 8,000 Gallons Turbo Ion Exchange Pre-Filter - Removes unwanted magnesium and replaces it with soft sodium to produce high quality pre-softended water. Permanently remove damaging metals like iron, lead, copper and other heavy metals from any water supply by chemically reacting with metals to physically trap them within the filter. Absolute must for well water - Stop rotten egg smell at the source by removing chloriamines, hydrogen sulfide, and other harmful contaminants/organics Prevent stains from forming in spas, and plaster or vinyl liner pools too. This pre-filter has a 8,000 gallon capacity and attaches to any standard garden hose. When water stops flowing, its time to replace the filter