Problem with our diamond brite surface... had it done maybe ten years ago, after a few years the brown spots started appearing and just getting more and worse over time! We have always had pool service too... the guy says he doesn't know what is causing this, he's never seen it before! So frustrated... can it be fixed without draining pool and re surfacing ???? We thought at first maybe the rebar metals were leeching through somehow... is this possible!! Thanks for any advice