The Protium D5 Polished Acrylic Pump top and Protium D5 Silver Pump Cover in the Tritium Reactor. The amount of inlet/outlet options on Protium pump tops was what enabled us to create this configuration. We often have questions about the inlet and outlet ports. There is one outlet port. This is because the outlet needs to have highly optimized fluid dynamics due to the impeller design of the D5. The rest are all inlet ports. You can use any port as an inlet but only one outlet port. Any remaining ports can be used as drain ports, temp sensors or parallel.