also...if you do plan to use the skippy, keep in mind that the venturi jets will have to be blocked. Those are also intended for a pump return to the pond. It it were me, I'd forget about the skippy. Build a nice gravity fed DIY filter and take advantage of that bottom drain and returns. A pond is so much easier to maintain with a bottom drain and the environment is so much healthier. My first "koi pond" (which I now realize was a water garden) had no bottom drain and only a skippy for filtration. It worked....but the fish never thrived. They didn't die.....but they did not grow either. The annual cleaning I did on that pond was a disgusting job. Poor fish lived in a septic tank.
A small pond can be done right though, by using "big pond technology" on a smaller scale and keeping the stocking rate very low. If you are only going to have those 3 fish in 1500 gallons, that is a pretty darn good stocking rate.
While I don't have any personal experience with Mr. Lim's preform, I do have several of his pumps and let me tell you.....those pumps are fantastic. Expensive....but VERY good pumps. He makes a good product.