I would pick some up. I haven't tried it yet - I have some, but have not had any staining yet. I have read some posts on the board who have used it. It may not take the stains that have been there for a long time off - but once they are off with ascorbic acid, it is supposed to turn the metals into crystals so that they can be filtered out. YOur water may not test positive for metals if the metal has already precipitated out onto the surface of the pool. If you post your numbers, I will help you through the stain removal.