I downloaded a couple of free patterns of music notes, to put on a Bow Tuck tote. I'm using gold embroidery thread on top and white poly/cotton thread in the bobbin. I can't keep the bobbin thread from showing through on top. I read my manual, about adjusting the tension, but nothing is working. My tension is normally at 4. I've tried lowering it to 2 and 3 and increasing it to 5 and 6. Nothing happens. Is there something else I might be doing wrong?