a new line will do you a world of good, but if your only fishing shallows i would stick with a floating line, thats what i use for flatties, in such shallow water there is no need for a sinking line.with the floating line when your pulling your fly across the flats, it will sink to the bottom and then when you pull your line, it will rise to the surface, a bit like SP fishing with a sinking line this wont happen it will stay near or on the bottom.