Thanks Carl and Mark for all the great info. I have to say I am not looking forward to next season without this forum. I am glad it was here for the 2 seasons I have had my pool open, I think I can handle most things now on my own with the knowledge I have gleaned here. At the moment, I think I will be able to swim 1 or 2 more weeks before things get too cold and I'll have to close. Why does the pool have to look so inviting when it is freezing cold!