I am going to be plumbing my Reefer 250 in the upcoming month or so and wanted to start ordering the parts I will be needing. I have drawn up a diagram of the general layout. I have done extensive research on what others have done, but still have questions. My biggest questions: What part do I need to connect the PVC to the Red Sea Return line before it goes to the DT? Is a check valve needed? Why or why not? Would you install the Flow Module right after the pump, or right before it returns to the DT?