That GH is way too low for the long term health of Rift Lake cichlids, I'm afraid.
Rift Lake salts are a mixture of the minerals needed by Rift Lake cichlids, specially designed to provide water close to the Rift Lakes. The salts need to be added to the new water at every water change before it's added to the tank so that the levels remain constant.
Ordinary salt, aquarium salt, is just sodium chloride which does not affect hardness.
Okay I’ll get rift lake salt, thanks for advice!