Sure, I will do my best to explain it. (if I don't ask away, and if needed
I will take more pictures)
The concept is have the return line start in the return section of
the sump. I will go up to just higher then the height of the sump.
It will "go" across than back down (on the outside of the sump) to the pump. I will post pictures to show more detail.
The bigger PVC in this picture is the beginning of the return line.
(the smaller PVC is for a shelf to hold a bag of carbon)
The "bigger" PVC in this picture is a check valve. ( I know check valves don't work 100% of the time) The purpose of it is to hold the water in the pipe while I primed it. It also holds the water when the pump is off. I know for a fact that it will hold for over 4 hours.
Another shot of the "T" with a threaded cap. I used this when I first set it up. With the cap off, I poured tank water into the return line to "prime" it. This way the pump is pulling water. (note I have only had to "prime" it twice -- initial set up, and when I moved the tank, never during a water change)
The return line is now heading back down (outside the sump) to the pump. I have a ball valve and union for when I want to clean the pump.
A very blurry shot of the return line going to the pump and than out of the pump back to the tank.
I hope that cleared it up somewhat, but if it didn't, ask away.