Gary
I do agree with Palladin in his recommendations, however I would simply include the skimmer line into the main pump inlet, ball valve both intakes (vortex and skimmer lines for adjustable flow rates) then send the rest of the water to the mechanical and bio filters at the other end of the pond. If you really want the BEST recommendation, I would simply use two 1/8hp pumps, one for the main line from the vortex and one for the skimmer circuit. Then send both lines up to the filters. This way, you could potentially run 6-7000gph total and turn the system over every 35-40 minutes. Just decide which circuit gets the U V light!?
The use of submersible pumps still scares the hell out of me. I've also had too many customers who we've retrofitted have their submersible pumps go out on them within one or two years. That's usually what prompts the call to us!
Mike