Crystal Clear Aquatics AAD00223 Zap-Cal Descaler, 16-Ounce Crystal Clear Aquatics specializes in Aquarium and Pond service products. Crystal clear c Zap-Cal Descaler 16oz Zap-Cal is safe for use with plastic ceramic rubber pvc titanium copper nickel and short term use with stainless steel. Crystal Clear Aquatics specializes in Aquarium and Pond service products Crystal clear c Zap-Cal Descaler 16oz Zap-Cal is safe for use with plastic ceramic rubber pic titanium copper nickel and short term use with stainless steel