This is my 3rd pond I have built over the years. I will probably use dual in line pumps in the range of 5,000 gph each. Filtration used will 1 55 gallon drum fitted with an uplift vortex chamber followed by another drum full of biological media. The filtered water then runs down thru a waterfall and back into the pond. I used this system in my old 5000 gallon pond with great results. I will also run a 40 watt uv. Everything is fitted with clean out valves for easy maintanace. I will stock it with natives (bass, catfish, gar, ect.) I live in southern cal so temps arent to extreme. I used to put my pacu, dovii, oscars in my old pond from late may thru late september into my pond. They loved the space.