while the tank is filling there are 3-4 drip streams pouring out from under the green cover at the top of the fill valve tower. dripping stops when fill is done. problem is the fill is noisy from the dripping, the drops hitting the water are distinctly audible over the normal water flow noise. i pulled the valve apart, didn't see any debris, etc. is it normal for these valves to drip like this? note nothing is leaking, the water all goes into the tank, its just the dripping noise is alarming, sounds like a roof leak. the tank is very resonant, rings like a bell.