Your aquascape looks very good and I am too surprised at how well the plants are doing bearing in mind the non-addition of c02.
Wish I could get the anubias to flower. That would be the feather in my cap in that scape, the Madagascar too.
Not sure if this is of relevance but Anubias Var Nana was one of the first plants I bought when I started my planted aquarium and I always remember feeling confused as to why their flowers would drop-off when I placed them within my aquarium lol. After reading into the possibility of my aquarium needing some form of c02, I started off using Easylife EasyCarbo and within a month the flowers on the Anubias started to form.
So if you want your Anubias to grow a flower or two I'd say the introduction of some form of c02 would be a good idea.
Then I must be content with no flowers then. LOLOL. Actually, you're right. I remember when I was injecting CO2 in my 36 way back, that's when I had anubia flowers.
Submitted this tank to ASW, thank goodness they extended the deadline to April 15. Whew! Will post pictures that I didn't submit later this weekend. I gotta take down the wall and do some work on it. Growth is too good and it's starting to choke on it. Will probably trim and redo the wall. LOLOL, it's like Riccia.