Two things about GH. If the water really is soft, with a high pH, it is possible you have some sort of water softener installed? Check into this; many of these use sodium chloride (common salt) to replace calcium and magnesium salts, so the water is "softer" but the sodium is even worse on freshwater fish. If there is a softener, test the well water on its own, before it runs through the softener. Depending upon the results, you may be better off using the well water.
Adjusting pH can only be done when it also involves the GH and KH as the three are related. The GH has the most direct impact on freshwater fish. This chemistry (GH/KH/pH) is something the freshwater side of the hobby has to deal with more than the marine side because the water in the oceans is basically the same. But freshwater can be very different depending upon the area. Water is a powerful solvent, and it assimilates substances like minerals, organics, etc as it passes over or through these, and the fish in that specific area have evolved to function in that water.