I'm getting ready to close my 2 year old inground, vinyl, BBB pool for the winter. I just removed the ladder and stair railing. There was quite a bit of white powdery residue in the galvanized cups and on the ends of the rails. Is this corrosion? Is there something i can treat or spray the receptical cups with? PH has been in the 7.4-7.6 range all summer, TA 80, CH 210. Thanks for any help
