What on Earth could possibly be wrong with a pH of 6.8-7? Are you breeding african cichlids?
If it's your typical aquarium fish, anything between 6 and the low-mid 7's should be fine. Honestly, below 6 is usually fine also, especially in a CO2 injected tank.
I personally feel that higher pH water isn't usually appreciated by aquarium fish less because of the pH and more because of the high TDS usually associated. I have no experiments to back this up, just the experience that the majority of fish could care less about pH.