I have read a few posts about sequestrants and how they work, and I've come up with some questions. If I understand correctly sequestrants prevent metals from forming precipitates. So if I were to encounter a pool where the water was clouded with rust, the iron has already oxidized creating tiny rust particles that are floating in suspension. Am I correct to say that a sequestrant would not help here? I encountered such a pool this morning. I've never seen such rusty looking water. There was only about 1 ft of visibility. My thoughts are that if it has already precipitated, filtration would be the best way to take care of it because it would be removed from the pool when you backwash eliminating the iron rather than just controlling it. What would happen if I did add sequestrant to a pool like this? Would it reverse the oxidation and return the iron into solution?
For that matter, does dissolved Iron show its presence visibly? I've always been told that clear green water usually meant there was iron. I'm just not sure if that means dissolved, or if it is a precipitate starting to form, or if I was just given bad information. We usually use the green water as an indicator of metals, and add sequestrant. That usually gets rid of the color. I have noticed that it also results in a rusty backwash afterwards. So I'm wondering if the sequestrant got rid of the green color, or if the iron oxidized and was filtered out, or was it a little bit of both? Would the iron have oxidized and filtered out even if I hadn't added the sequestrant.
What about other metals? Does it work pretty much the same as Iron (oxidized products are insoluble and will precipitate)? What color water would indicate other metals?