Hi Don, I also have a small 1000 gallon Koi pond in my greenhouse and you really need to look at the electricity required for your pump. You might find that it would be alot cheaper to get a true pond pump. I am using a 1900 gallon per hour pump that requires 200 watts. My pool pump for an above ground pool requires 750 watts! Am planning on changing over to a pond pump for my pool to save money once I design a filter system. I also am planning on using one in the large pond, 1/3 acre, to run a water wheel and then run back into the pond will help areate the water also. Bob