The reservoir serving my area has very soft water. The water company, according to its reports, modifies the water to come out of the treatment plant pH 9.3 and alkalinity of 40 mg/l. By the time the water comes out of my tap the pH has dropped to around 8.3, and both GH and KH are 2-3 degrees. The water in my tank tends to settle at pH of 7.8-8.0. (Neutral substrate, no wood, no CO2)
My eventual goal for the current tank is to keep softwater fish, like tetras, which prefer a pH in the 6-7 range.
I'm trying to figure out what to do with my current water conditions, or if indeed I should bother to do anything. If I were to cater to the preferences of the fish I want, I need to drop the pH. However, most methods I know to drop pH involve dropping the KH. Since the hardness is already under 3, I'm not comfortable with dropping it even more. I don't want to trigger pH swings by removing the little buffering capacity the water currently has.
LFS staff didn't really have any advice beyond noting that the local bottled water has a pH of around 6.5. Uh, no. I'm not doing water changes with bottled water.
If it comes to that, I'll keep endlers and danios instead of tetras.
I'd rather not get into chemical buffers if I can avoid it. I'm not confident I can keep the water parameters stable. Should I leave well enough alone and figure the tetras will deal with the pH as long as the water stays soft? Drop in oak leaves or something acidic like that? Cultivate a love for livebearers instead of tetras?