I replaced my 27' X48" AG liner yesterday and it's at 31" right now and my daughter turned the water off until I get home from work. I read my through the wall skimmer instructions and they state: back gasket goes between skimmer and pool wall, then liner, then front plate gasket and finally front plate. I have read on these forums that it should be gasket, then liner and then front plate. Why the different order? What purpose does does the gasket between the liner and pool wall have? Keeping water from going down in between the liner and wall? Oh and what about the wall foam? I am assuming trim it wide of the opening and keep it out of the layers entirely. Is that correct?