I have an MRC Pro-1 external skimmer. The recommended feed rate is 300-500 gph. However, in the installation instructions it recommends installing above the sump to decrease back pressure. I will have it mounted on the floor at the same height as the sump, as seen below. My question is would the back pressure affect calculating the power of the pump needed much like head pressure of the plumbing? If so is it a similar calculation to head pressure in terms of distance traveled and elbows, etc.? ... oriIs back pressure just something that will make the skimmer less effective and don't take it into consideration when choosing a feed pump?