I noticed some burnout where I hadn't previously had any issues. I turned on the zone and saw that the sprays weren't reaching that area. It seems like the pressure on that zone is much lower than the adjoining zone that has the same number of heads. I checked the filters on each head which were fine and left the last head off to see if I could flush it. The water would just bubble up and wasn't a gusher. This is either a valve issue or a leak, right? If I turn the spray heads off at the head and my pump still runs, it would confirm a leak? I don't have any wet unusually green areas. Thanks, BL ps: I've been fight with some voles (though not in that area).