confused on which pump to use


New member
i want an internal in sump pump, i am using insted of majorty pvc im using tubing one inch compleatly clamed and barbed on i only have one 90 degree angle on one return bulk head and the other bulkhead i have two return pump bulkheads and two drains all sepirate from each other so if one clogs it doesnt over flow the tank , but all holes are one inch my tank is 5 ft off the ground from the top return and 75 gallon and da 40 gallon sump, i dont have any idea how to determin the ammount of flow i need on the return idk how much draining i have its gravity based