The 207HC Level Master™ is a water driven chemical proportioner that automatically maintains a constant supply of highly concentrated ready-to-use solution in a paired tank (sold separately). When the solution in the tank drops below a pre-set level, this venturi injection system uses city water pressure (40 - 80 PSI) to draw and blend a high concentration of chemical into the water stream to create near 1:1 dilution ratios. The solution replenishes with a water flow rate of 2.0 GPM @ 40 PSI and will cycle continuously.