You'll do yourself a favor to remove as much of the iron as possible before filling the pool. As far as chlorine goes, it's pretty much the only thing you can use that will truly sanitize the water, including viruses as well as bacteria. With an indoor pool you don't need to keep it very high, since you won't be using any stabilizer. Are you sure that it's the chlorine that you're sensitive to? Many people that have burning eyes, dry skin, etc often blame chlorine when it's not always the real culprit....