Fresh water tank vent 'dripping noise'

[sandycohen]

Hi All -

One (of two) of my fresh water tank vents is making a noise that basically sounds like dripping water. I say making the noise - it's obviously echoing or carrying the noise from somewhere. My first thought was this is water condensing in the lid of the tank and then dripping back down, but why would it only happen with one tank then? I have them both open, so they should be equally full.

thanks

Sandy