I have a 14', 4-foot deep Bestway above-ground pool and have noticed rust developing on some of the metal poles on the top frame. One thing I've pondered was replacing the entire frame, including the vertical poles, with PVC pipes. Has anybody had any luck with doing so? What size did you use? What fittings/couplings? Did you fill the pipes with anything to weigh them down or ensure they could support the weight of the pool?