Chemical metering pumps are positive displacement pumps that dose liquids for various applications such as wastewater treatment, chemical processing, and manufacturing. Diaphragm chemical metering pumps use a flexible, reciprocating diaphragm to dose liquids. These pumps are less likely to leak during operations and more energy efficient than peristaltic chemical metering pumps. Peristaltic chemical metering pumps use rollers and an elastomer tube to draw in and dose liquids in a system. These pumps induce low shear pressure onto the pumped liquids. Progressive cavity chemical metering pumps use a helix-shaped rotor and an elastomer stator to dose liquids in a system. They are suited for handling viscous liquids and put minimal shear pressure on fluids. Repair kits for chemical metering pumps replace commonly-worn parts. They keep pumps operating and in good working order.