I know I have metals in my well water so while I was filling the pool this year I added a sequestrant - Metal Free. However, the water is still colored. It is clear, it is just tinted a greenish/brownish. The coloring appears to be related to me adding the chlorine. I don't think this is alage - there is nothing on the sides of the pool and the water is clear, it is just colored. So do the sequestrants target specific metals and/or does it have a shelf life?