I change the water & gravel vac weekly, about 20% of the water, and last I checked my ppm was 10
I get the feeling your problem, will not be solved by medication, but more frequent and larger water changes.
I consider 20% per week for cichlids paultry.
On my cichlid tanks I try to do 30%-40% every other day.
From the info in the opening post, it seems your problem is chronic, and although meds at times have temporarily put a band aid on it, you have never got to the root of problem.
Most Amatitlana species come from pristine, moderate flowing streams, and rivers, or from low nutrient lakes, and although a few species can be moderately tolerant of nutrient soup, they do not do best with if water quality is not constantly renewed.
With an only 20% water change per week, after a couple weeks, tank water becomes a broth of pheromones and hormone, that are a breeding ground foe bacteria that cause intestinal issues, or other chromic maladies like HITH.
And cichlids (with the exception of a few Tilapia), do not cope well with that nutrient soup.
If your current routine is all you have time or ambition to deal with, fish from swamps, and less than pristine habitat and waters and deal with wimpy water changes may be a better choice. i.e. anabantids that thrive in nutrient loaded rice paddies.
Those fish that can use atmospheric oxygen, and have adapted to those soup like conditions.