Duplicates constantly delivering water to the same buildings

This happened to me as well for a while.  There was a puddle of water nearby and the duplicates got all horny over that terrarium.  They kept shoving water down the little plant until that nearby puddle was gone.  Easily 200kgs dumped into the terrarium.

The problem is... if they are getting their water from a little puddle, they are only carrying on average 1kg of water per trip.  The algae terrarium uses more than that by the time they come back with their next drop.  The dupes will prioritize the little puddles or small water sources over the large ones, this can be helpful for cleaning up your base, but also can cause complete colony loss if every dupe is pulling water out of a small puddle (when there is a larger one available) and doing NOTHING else.