Midwater
I'd be curious, to see some simple  testing (if you have the time, and energy)  in or around the waters near where you live?
To see,  if the same is true there where Dats live, as in tropical areas that match up with tropical areas in Panama where my cichlids come from.
So often we see erroneous info that our fish come from nutrient nitrate filled areas.
yet where I test, nitrates are non-exiistant.
It seems to me aquarists  are often bamboozled into a false sense of nitrate reality, when the truth is far and away totally different.