What is the correct balanced equation of Photosynthesis?

A complete Definition of Photosynthesis: An anabolic process by which chloroplast of green plants and other phototroph’s synthesize carbohydrates (glucose) and evolve molecular O2 as by-product, using CO₂, H₂O and sunlight.

Till 1930, it was believed that photosynthesis is just the reverse of respiration.

An experiment conducted by Ruben, Randall and kamen (1940) proved that O₂ evolved during photosynthesis comes from water, not from CO₂.

For the experiment, they used heavy radioisotopes of Oxygen (O¹⁸) in water (H₂O¹⁸) and CO₂¹⁸

Experiment 1: When photosynthesis occurs in the presence of H₂O¹⁸ and normal CO₂, the heavy isotope was found in the evolved O₂

Experiment 2: When photosynthesis occurs in the presence of normal H₂O and CO₂¹⁸, the isotopic oxygen is not evolved.

The experiment for the first time proved that the oxygen evolved during photosynthesis comes from water.

Original paper

Then the conventional equation was modified as 6 molecules of H₂O is not sufficient for the evolution of 6 molecules of O₂.

Now the correct balanced equation of photosynthesis is 

Reference: Ruben, S., Randall, M., Kamen, M., & Hyde, J. L. (1941). Heavy oxygen (O18) as a tracer in the study of photosynthesis. Journal of the American Chemical Society, 63(3), 877-879.