OK I'm new to pool water maintainence and need some help from the experts. Here's the story: first year with a pool18x36 iunground. Filled it with my well water which has iron, pool went to tea brown within 10 minutes. Couldn't see anything. Had it tested came back positive for iron which I knew it would. Anyways I put some metal out sequestering stuff in the pool and two days later the pool was clear with a lot of precipitates on the bottom whish I vaccumed out. Swam in the pool this past weekend and had the water tested. This time the test said no iron and so i added two more bottles of shock and the pool turned brown again albeit a lighter shade of brown this time (can still see through the water whereas the first time you couldn't) so my question is how do I remove all the iron so I don't have to keep spending money on metal remover everytime I shock the pool?