Nice one, I'm only a little jelous of your success so far! I'm coming up to day 50 now and Ammonia is still at 3-4ppm... My eyes keep playing tricks on me and I think I see a light green tinge, but alas no it remains dark green...
Not sure what anyone else thinks and if I were you I wouldn't listen too much to the most unsucessful fishless cycler on the forumTM (that's what I'm naming myself anyhow) but if your Ammonia is 0.25 today I'd think about dosing back up again. All my troubles started when it was stuck at what looked like 0.25ppm for several days.