Just had a expensive custom storm door made for an arched doorway, but the installers can't get it to close. WIth the main door open, the storm door closes easily, but with the main door closed, the storm door meets too much air resistance and won't close. If we adjust the pneumatic closer to pull it shut faster, it slams too hard when the main door is open, but still won't pull the storm door shut all the way when the main door is closed. The installers are stumped. I can't be the first guy to have this problem. What's the answer?