I'm struggling with my group and hith. Such a problem for geos
Being from Hamilton Ontario, this is not surprising, you probably get Great Lakes water, which is generally hard (high conductivity), and high in pH.
All the parameters that are over the top for black water species.
And if you are not doing large enough water changes to reduce nitrate to below 5, those nitrates in combination with the conductivity provides perfect conditions for bacteria to grow, these black water Geo's have not evolved resistance to.
My water source in Wisconsin was Lake Michigan, similarly hard, high conductivity water, soI had to do 30%-40% water changes every other day to keep nitrate at a low enough level, to avoid HLLE, and collect leaves to soak for the anti bacterial tannins added during water changes.
Neutral of higher pH endemic Geophagines (like those from west of the Andes), or Gymnogeophagus from Brazil or the other countries south of Brazil did much better in my type water.
For the black water types, an RO unit could also a positive addition.