I have no clue and don't even know how I would tell.
Eventually after sewing enough it stopped making the weird noise it was making (never did figure that out) and I played with the tension some with 2 different thread colors. Ended up putting my machine on 3 because that seemed to not pucker the fabric at all. Although I could see the bobbin thread on the top of the fabric, but never saw the top thread on the bottom of the fabric.