Here is an update on a post from December 9 based on this procedure where I applied different doses of carbon dioxide to pond water confined to plastic bottles. Note that after 14 weeks, the strongest color is found in the bottle with the highest dose of carbon dioxide. This is not at all evident in the early weeks because the high dose of CO2 seems to have an inhibitory effect on algae. However in the long run, I seems that this dose results on the highest algae density because the other bottles eventually run out of carbon.

14 weeks

8 weeks

3 weeks