How many turns of the calvin cycle for one glucose?

6 turnsTherefore, there is only 1 net carbon produced to play with for each turn. To create 1 surplus G3P requires 3 carbons, and therefore 3 turns of the Calvin cycle. To make one glucose molecule (which can be created from 2 G3P molecules) would require 6 turns of the Calvin cycle.

Distillation.  distillation is the correct answer.