Hello all.  We have an extended aeration tertiary treatment package plant that we need to increase the hardness in the final effluent.  The water supplied by the park is generally low pH and we add chlorine @ approximately .7ppm and also add aquaMag to coat our pipes to keep the low pH from leaching copper from the supply pipes.  Our wastewater treatment plant has a copper limit associated with minimum hardness.  Right now, we are adding lime to help with alkalinity and Poly-Aluminum Chloride in the Tertiary units.  Our pH is around 8.5 so we are reluctant to add more lime.  Is there something that we can add (like Calcium Chloride or Magnesium Sulfate) to increase the hardness of our effluent?

Thanks!