I have some questions someone may know the answer to. I have a koi pond I dug myself, approx 1500 gals. It has a spouter on 1 end, and large rocks and two waterfalls on the other. I have 4 koi, 10-12 inches and two 4 inch goldfish and new small fry, which I plan to get rid of when they get larger. I have 1 submerged pump which is in a submerged file folder/lava rock/ furnace filter homemade biofilter I built from a plan on the internet. It is a 300 gph sump pump. I use 1 1/4 inch pvc from the pump to two ball valves, then to the waterfall and spouter, which I can adjust. It is becoming a hassle to have to go physically into the pond, unhook the plumbing, remove the filter/pump and clean. I plan to put in a small pump with minimal tubing and a long cord for the spouter. Then I plan on installing a pool pump style external pump, 4500 gph, with a swing valve and leaf basket/primer pot on the input. But it has 2 inch plumbing hookups in and out. Can I use my 1 1/4 plumbing or will it reduce the gph a lot? On the output, should I use 2 inch or 1 1/4 inch plumbing? I also want to add a pressure filter with UV but I guess the gph is too much, can only afford 200 to 300 for filter. Thinking I can put two ball valves with a Tee and have some pressure go to the filter and then the waterfall and the other to go straight to the waterfall. Will this work?
Thanks.
Mike