What is normal pump pressure range?

The lower the pressure the less work the filter is doing, 7 to 10 psi is a good pressure. Another tip would be to put your hand by the outlet where the water goes back into the pool if the water pushes your hand away you have good pressure also take a pressure reading at the filter, if you put your hand at the outlet and the water does not push your hand away take a pressure reading, backwash the filter, put your hand at the outlet again if it pushes it away go back to the filter look at the gauge and see what it reads now, and that would be your suggested low pressure for your filter.