I would expect for a 10,000 gallon pool you could quite happily run on 1/4hp pump if you don't mind people laughing at your little pump, My pool is a little bigger and you can read from my signature that I am using 0.08hp I don't mind people laughing at my little pump but when they see how little my electricity bill is for the pool they don't laugh anyway they just ask me to re do their pools!