I went back an looked at the proposal again and I had made a mistake on the pool size. It will be an 18,000-20,000 gallon pool instead of the 28,000. Can you recommend the correct size sand filter for this size? I will have either the variable speed or the 2 speed pump installed. I have not been given the option for the 2 speed pump but that looks to be less of a problem in the long run (less electronics and just good ole mechanical timers and relays).