I need help with buying some new water tubes for my winter leaf cover. I notice that online stores measure them in gauges. But I thought plastic was measured in mils? Anyway, the stores tout the higher gauges as being thicker and better. However, I thought low gauge number were thicker,(as in sheet metal). I would appreciate any advice on what type, gauge and where to purchase water bags. Also, is there any suitable product that can replace the water bags?