I have a Steelheader II pontoon boat. Over the last couple trips I've noticed a slow leak in one of the tubes. I tried tightening the valve which didn't resolve the issue. I then tried to see if I could find a pinhole with soapy water, which again was unsuccessful. I called the manufacturer and they recommended I remove the the valve, spray fix a flat directly into the tube, shake it up, and reinflate it. Is this a common method of repairing inflatables? I have found nothing online to support this method of repair. Does anyone else have a better solution to locating/repairing the leak?