What is the pH of the tap water?
I don't see pH of 8.2 as problematic, or unsafe, its just what it is, and will determine what type fish to keep..
in nature Lake Michigan next to where I used to live pH averages 8.4, so my tap water reflected that reading.
Lake Gatun in Panama near where I live now, pH can be as high as 9, my tap water reflects that and averages around 8.2 after treatment.
The rift lakes of Africa, between 8 and 9, so are many natural bodies of water in Mexico.
If the natural pH of the OPs tap water is 8 or above, the fish kept should come from high pH waters.
Fish from naturally low pH waters should be avoided.
Here are some examples of catch location water parameters.

Now the nitrate is a different story, most natural water have aero to low nitrate, but this is easily dealt with, with water changes.
