You can actually drive the ph down 2 different ways that is much safer than chemicals. One way is adding a couple bigger pieces of driftwood. It will release tannins, which is tannic acid, which will lower the ph some, and will lower it slowly over time. The other way of driving the ph down safely is with CO2 injection. It's great for planted tanks, but if not planted, I guess it could be used if you really need to lower the ph, and then run a ph controller to hold the ph at a certain level. A 3rd way is mixing in some RO/Distilled water to your tap water, but that will also bring down your buffers some, and if brought down too much, will make the ph become somewhat unstable. My tap ph is around 7.8 out of my faucet, and after having 2 pieces of driftwood in my 2 tanks for a couple months and doing normal PWC's without altering the ph, my ph was hovering around 7.2, and even got to 7.0 on occasion, in the tank. In my planted tank I also have driftwood, as well as CO2 injection driving my ph down to 6.4-6.6.
But also remember, even at higher ph's, fish are still happy if the ph is stable. They WILL acclimate just fine. There aren't too many fish that are too fragile to acclimate and be happy. If the ph is stable, you will have happy fish.
So my recommendation? If you feel you need to bring down your ph a little bit, get 2 nice sized pieces of driftwood, and either boil them or soak them for 3-4 weeks, and then add to the tank. My preference is either African or Malaysian, as they instantly sink and won't have problems with it floating. Then after adding to the tank and the water starts turning a little brownish color (tea colored), that's just tannins and are safe for the fish. You can run carbon to remove it. So that's my 2 cents worth. It's the safest way to bring the ph down some over time.
And the biggest key to happy fish is PH STABILITY. NO CHEMICALS.