Saurabh As far as I remember I saw this place to my left when walking towards Chandratal.It seemed to be at a distance of 2-3 Km from Chandratal. It looked like a glacial melt to me.I have also taken pictures of that. Will post pictures of the same after reaching home.
The Samudri Tapu is origin of Chandra, yes.Samundri Tapu is a glacier, the originator of Chandra river. The water body definitely points towards the glacier and might be a part of it. Tanveer did have a couple of shots of the glacier, check out his 2012 log. Smugmug is banned at my workplace
Also Tanveer wrote about how its accessibility. You basically have to rappel across the river. So yes, inaccessible until you find a bridge to cross over and walk all the way.
There was another thread of a gentleman who had stayed at the Chandratal camps for 3 days and explored the surroundings. It had even more details. Can't seem to find it now. But for all I know, this water body is the leftover of a retracted glacier (Samudri Tapu?) which essentially forms into an independent glacial lake in due course of time.The Samudri Tapu is origin of Chandra, yes.
But the one on left is not the same. Two are different.
Reference is here in Tanveer's log http://www.bcmtouring.com/forum/travelogues-north-india-f61/lake-moon-spiti-sprint-t26365-6/#post325908
& yes, it surely looks like a stream coming out of Glacier now, as I thought after seeing those GE pics.