Spa cover not sealing in cold temperatures.

[capt835]

I purchased the CVR-RSQ-RHT Spa Cover at the end of 2009. I noticed last night the cover was raised on the two ends. I used the clips, which were tight when I connected them last night. I had to lean on the cover to get the clip connected. I noticed this morning the ends were approximately 1/2" up off the tub. The temperature overnight went down to 0 deg. I'm thinking the foam or vinyl contracted in the cold and lifted. I will probably resort to using rope to tie the cover down. I did check for obstructions such as ice under the cover. I use the tub about 3 times a week. Our temperatures have averaged 25 deg at night until this weekend. We have had snow almost weekly since Christmas.

[MaryH]

Do you have the order number for this spa cover so we can review the cover selected to determine what is causing this?