It looks like just all water to me, clear. I did, a few minutes ago, see a couple of guys out doing what looked like scrubbing down that white area. House keeping chores I imagine. :)
Note beastieboy that it is almost 12:48 central time and the right half of the tubes (except the right end tube wich appears greenish) all seen to be crystal clear and later this afternoon will reflect the green shadow from the left.