I pressure washed a water based stain off of my deck and restained with an oil-based. The deck was properly seasoned or primed before I ever stained it the first time. The oil stain still allows a hard white residue to appear above the knots in the wood. A rep. from the stain company looked at my deck and claims it's the wood, not the stain (surprise!). He said that there is moisture rising up from the bottom of my boards?? Correct, or just a sham to deny me of my refund? His suggestion was to scrub w/soap and water (have done it, many times, didn't help)......he said it would eventually go away!! Please give me any advise you guys have? Thanks.