Mary, I'm in Wilmington, DE.

That's the thing that bugs me about this. We don't know how it happened and we have no idea how to prevent it. When I closed my pool for the first time in 2005 my plaster hadn't cured yet (pool was built late in the season) so I wasn't surprised my PH was high at the start of my first full season. The plaster was pretty smooth at that time though. I would have expected my PH to have been somewhat better when I took off the cover this year but it was sky high.

What king of cover do you guys have? I have a mesh cover and I'm still wondering whether that can be a negative because it's exposed to the elements. My hardness was very low as well. I had to pump a lot of water out this year due to winter rain, so the the mesh cover caused the water to get quite diluted.