I put down some 3 1/2 inch pine flooring, sand with 80 grit then 120 grit and vacumed,and have a good smooth survice, used 1 gallon sand sealer,let dry 24 hours, sanded with 120 grit and vacumed, applied coat minwax polyurethane (fast drying), sanded with 120 grit and vacumed, color was light so mix 6 oz. can of minwax golden oak with rest of gallon. when I all dryed I have spots not of staine but same spots that was on first coat.Usually second caot blinds them out. I have resanded floor again. What am I doing WRONG!