blue grey water coming from tub
I have a mystery that I hope someone can offer some suggestions about. The bath tub in the apartment over my garage has bluish grey water coming from the spout. The tub also has a shower with an old hand held shower head. My tenant turns on the tub water to get it warm before showering and sometimes it comes out a bluish dark grey for 10 seconds or so. I thought maybe it was something disintegrating in the old shower head but as he turns on the tub first that doesn't seem likely.
I've read about blue water syndrome from corroding copper pipe but the color doesn't seem to match the description. I really hope it isn't that! No other fixture has the problem.
Any ideas anyone? I'm attaching a picture of the water...