I have two sinks, on one countertop in the bathroom. I use one 95% of the time. I noticed tonight as I was using the main sink that the other one started making gurgling or bubbling sounds and that I had a leak coming from a few places (from the wall, and where the sink pipe fits into the bendable PVC). Not sure why the one I wasn't using was leaking and the one I was using wasn't leaking? I reconnected everything, but still have the same issue. One thing I did notice is there was quite a bit of black sludge and I did my best to clear it out. Any suggestions?