I bought this house December after eight months in short sale. The gunite pool was unopened and uncovered for at least two, if not three, years. When I saw it in April 2012 the water was very low and the pool, apart from the shallow black water, looked good and the gunite was white. Fast forward through a snowy winter and a pool filled to the brim with black water to this weekend. The plan was to drain and acid wash it. What we found were two feet of leaves at the bottom of the pool. After the leaves were removed and the pool power washed, we discovered that the pool bottom had gone from white to black. The gunite is also a moment away from concrete, so an acid was is now out of the question. Anybody know why the pool bottom is black? Algae? Tannins? Metal (the well water here is very high in iron)? Any suggestions/solutions? Here is a picutre.[attachment=0:3jltc6k8]pool051013.JPG[/attachment:3jltc6k8]