amazon river low ph and calcium?

[ricey0809]

so i think i have read somwhere that the amazon river has low ph and calcium.
Now i was wondering if i had amazon fishes such as buckthooth tatras "exodons" with a PH of 7.0 or a little higher and rich in calcium, would they not do so good or maybe even die?

 

[captainawesome]

I couldn't say for sure, but from what I hear you are supposed to keep neon tetras in RO water, and I didn't have enough RO water in my system to fill a tank all the way with it....soooo I put what I had in with them and the rest tap, and they seem to be doing fine. its been nearly a week. Mesa AZ water is some of the worst in the nation, too