Algae in water dissolving into oxygen bubbles only creates half the mass (Intentional?)/

Basicallly, the title. I was testing that new mechanic where algae debris dissolve into oxygen when in water and exposed to light, thinking that it's supposed to be a slightly more efficient alternative to Oxygen Diffusers. However, for each 1 kg of dissolved algae only 500 grams of oxygen are created. Tested it with different masses. For small amounts with the bottom cap of 20 grams per second, it creates an oxygen bubble about every 5 seconds, and that oxygen bubble contains only 50 grams, while 100 grams of algae disappear.