of course, I'm not in Oregon, but Indiana is not exactly Florida either...however, I have the same pool as you. My water has gone from 70 to 80 since saturday and that is without a solar cover. these pools are just so shallow that they really do heat up quickly during the day...you just need to save as much of that heat at night as possible...seems to me that the solar cover would be a great way to start (and reasonable expense)...personally, I enjoy a bit of a nip (slightly chilly water)...

could the pool experts here tell me if there is a correlation between temperature and chemistry? in other words, will it be easier or harder to moderate the chemical compostion as the water temperature fluctuates versus keeping a more consistent temp with assistance (solar cover or heater)?