Throw some crushed coral into the substrate or into a stocking in the filter. Give at least a good handful of it. Or fake coral skeletons work too, or crushed shell, etc etc. Anything coral.
Or you could get some limestone rocks.... those'll raise the pH too.
Or you could manually add some baking soda (the amount depends on how big your tank is). That also raises the pH instantly, but you need to add more to buffer the water each time you do a water change.
The pH for africans should be 7.8 up, i usually stay between 8.0 and 8.2
-Diana