I have a megaquilter and I am having a heck of a time with the tension. The preset tension is 3.5. So is that tension setting with the foot up or down? I have noticed that there are little dots on the top of the quilt when I sewed with varigated thread. On the bottom I saw dots too. At first I thought it was the top thread and changed the tension and no matter what I did it didnt change the sewing. Any suggestions?