There is loss from the travel yes. For my 55 tank, I built a 20 long sump. It is currently using a mag 5 as the return and a CPR overflow feeding it. It is working out great, I made each of the 3 sections 10 inches long. This can easily be modified by making the return area smaller for more room in the fuge or intake area. Though in my 10 inches of intake, I have my skimmer, a uv
sterilizer, and another pump that feeds my dual reactor. Lots of room in there. My fuge has some cheato, a money plant, and 5 mangroves.