Tension on my sewing machine is wrong!!!help!?

i have a brother XL 2600i sewing machine and as much as i try i can't get to tension correct. I read the manual and followed the instructions. it seemed that the upper tension was tight but after I lowered the tension the lower thread was too tight.i tried setting it at 4 so it could be equal but then the upper thread is too tight again.please help, i'll like to get back sewing soon!!!