Hi, have read all the posts but still have a big problem with a yellow/orange sun tan mark at the water line.I have added HTH clear pool emzynes liquid which does clear the surface grime off the water but it is still clinging to the sides. Has any one found a realy good water line cleaner as the one i use isnt great. Am running the pump for 10 hours to try and filter more, still no joy. Has anyone found a better solution. Thanks Paul