Seneye Ammonia Reading?

[LeeAberdeen]

Does anyone know if a seneye detects both toxic and non-toxic ammonia (or is that ammonium if it's non-toxic)? Mine is showing ammonia at 0.049, which I think is on the verge of a stress level, but my discus appear very happy. Just wondered how the seneye reads ammonia levels because I've dosed with prime a few times over the past week and yet the ammonia reading stays roughly the same at 0.046 to 0.049. There's ammonia-removing media in two filter trays and purigen in another two which, combined with the prime and regular water changes, means there should be hardly any ammonia at all? I know my API test kit detects non-toxic ammonia too and, as that's showing roughly the same levels as the seneye, it seems to point towards the seneye doing the same thing. Does anyone know for sure?
 
Thanks for your help.