CuLator Ultra 4.0 removes 4 ppm total dissolved metals from your pool water, which prevents pool staining and water discoloration. The goal is to have 0.0 metals in your water. CuLator eliminates stain-causing metals like copper, iron, manganese and lead from pool water. CuLator Ultra 4.0 is perfect for pools which have a lot of metals, larger pools, pools on well water, pools which have had a copper coil heater “blow out” and commercial pools. The CuLator Ultra 4.0 may also be used as a seasonal treatment for general maintenance and during pool stain treatment.