The EasySet is the donut, right? Since you must take down the pool every year, it's probably just easier to fill with the iron-free water. Intex filters will handle ordinary conditions, but serious deviations go beyond what they can do. It's your decision but even a decent small pump and filter will probably cost more than the pool itself. Is it worth it? That is your decision.

Been there, done that--I had a 15' donut we used for 3 years.