I don't know how long the metal stays bound to the sequestering agent, maybe waterbear can answer that one. I do know that you have to add a sequestering agent when you add a lot of fill water, on the bottle it says to add a weekly dosage, but I only add the sequestering agent when there is a lot of new water in the pool, or I see some stains starting to form.

I am still trying to find a way to take the metals out of the water that's not too hard or expensive. I know there are ways - but I don't know any that are easy enough to make it worth it for swimming pools. You can drain and refill, but you have to find a water source that doesn't have metal. I have a well, so I just deal with it. I keep researching......