I have 3 embroidery machines (2 Pfaff and 1 Brother) and I never adjust my tension. When you thread the machine with the foot up, the tension assembly is open for the thread to slide in. When the foot is lowered, the tension is applied and it tightens up. You won't be able to pull it thru--if you can then it needs servicing. I don't think you need to worry about it unless the thread is breaking when stitching. And the correct ration on the back of the item is 1/3 bobbin thread and 2/3 top thread.