Well, now that we purchased a pool package, we feel that a heater will be needed. The grandkids might not mind the cold water, but I don't think my arthritis will! We have a gas well on our farm, so have free gas up to a set limit which we only use half of. So, a natural gas heater seems like the way to go. Any suggestions on size and brand? Pool will be a 30 ft. round, ag, 52" high. Thanks!