I used to live in Wisconsin, normal water is in area is in the 8s pH (Lake Michigan 8.4-8.6 depending on the season), so I kept fish that were endemic to that type high pH water.
These include African Rift Lake species where pH approaches 9 (Cichlids of L Tanganyika, Malawi, and Victoria), or those species from Central America (which include many cichlids, live bearers, and even some tetras (genus Astyanax). Australian rainbows also thrive in high pH water
Trying to keep South American Amazonian species, or some soft water Africans is a losing battle, unless you want to set up an RO system, or collect rainwater to mix with tap for every water change.
I find products like pH down to be a waste.
Why stress out?
Select from the many species that like high pH water, and forget the rest, it will make your life so much easier.