Best bet is to determine what your fish like then compromise on a proper ph solution such as Proper Ph 7.0 for barbs.
I'd even argue that the best compromise is that unless you plan on breeding or keeping wild caught fish, the vast majority of commercially-bred fish will adapt and thrive in a wide range of pH. My research and experience has demonstrated that fish can adapt very quickly in pH; to the extent that I'd say that pH shock is almost nonexistant. It is changes in hardness that are far more stressful; and that most cases of pH shock, were probably in fact hardness shock.
It is only anecdote, but I can tell you that in that same water of pH 8.2-8.4, I have had many species breed, even though the pH is well outside their "preferred" range. Lemon tetras, tiger barbs, and bronze cory catfish have all bred in those waters, for example. And, all of them and many more species have led very long healthy lives in those waters. I wasn't even looking to breed them, they were happy enough in their life to breed on their own.
Whereas, if you use chemicals like Proper pH 7.0 to try to adjust water conditions, that can be more stressful than a wrong but stable pH. Those chemicals work by breaking down the KH of the water (changes in hardness) and then re-buffering at a different pH. Water is a tricky beast, though, and often in the short-term it looks like you've adjusted pH, but in the long term, it will drift and move again. Almost always, the hardness is not built back up correctly or in a stable manner. And, again, it is changes in hardness that is more stressful for fish. Also, most of these pH adjusters have large amounts of phosphates which can cause explosive algae blooms.
So, in conclusion, I would strongly advise avoiding the chemicals, and just stick to commercially-bred fish. They will adopt to your local water conditions, and without chemicals, the local water will typically be very stable. If you chose to go the wild-caught or breeding route, I would start with RO of distilled water as a blank canvass, and then use the various mineral mixes to build up your water to the target conditions. Again, still no chemicals, and yet achieving the desired water stats. Most of us aren't interested in this though, and our tap waters are good enough that most fish from your LFS will be able to live long, healthy lives in the water our local municipalities provide.
