We purchased a used 1-year old Intex Ultra XTR rectangular pool from someone who couldn't keep up with the maintenance under his trees. We are first time pool owners and we have used TFP as our primary source for all our site prep and future chemical undertakings. The problem is there is some dirt that does need to be cleaned off on the outside, but our biggest concern is the stain around the top edges inside and outside the top rail that looks like a combo of mildew/algae. Would you recommend cleaning this before filling or wait until legs are set up in place? Any recommendations for type of cleaner would be wonderful. I thought of possibly oxiclean, but don't know the impact of this on the liner. Much obliged for your expertise!