In my tanks floating plants take care of ammonia, nitrite, and nitrate beautifully, but if you have an emergency and get high ammonia levels and you've got Seachem Prime you can always overdose it to detoxify ammonia. Among other things like removing chlorine, Prime converts ammonia to ammonium, which isn't nearly as toxic. I think there might even be instructions on the bottle for using it to treat ammonia. They also have Amguard, which does the same thing.
PS: Cool looking set-up. Ive wanted to do an all pots sort of thing like this. They always look so nice and tidy, haha. Is that a "sensitive plant" growing up above the water line near the bottom of your picture?