You have a great batch! I use cinnamon only for both my colloidal silver and colloidal gold. I noticed for colloidal silver in 1000 mL it only takes 4 drops of cinnamon to completely reduce. When I compare 4 drops with a batch that has 16 drops, the color is the same. With colloidal gold I have noticed that more is needed with 1000mL. I think its important to use more reducing agent than less especially with my Gold Chloride process, since you dont want to have any Gold Chloride left over. If one doesnt like the taste, you can put it through a Brita water filter and it filters out the flavor quite a bit. I have been wondering if the microwave, after making a batch, has the ability to reduce nano-particles, I have yet to try it? Keep up the good work!
I think another factor you may want to record in your observations is "turbidity". Is the turbidity less when more cinnamon is added? is the pink a sign of less turbidity and smaller particles? Also I agree with Kephra that if not enough salt is used you end up converting less of the gold chloride to metallic particles. These water filters are great when you finish because the seem to get alot of the left over sediments out of the solution before your ready to drink up!
Cheers!