Email marketing soft

I have freshwater and it is very very soft water.

I’m looking to get a few lake Tanganyikan cichlids for my tank but it is currently filled with soft water. I currently have a few tiger barbs in there just to get my tank cycled and will be removing them to start up another tank with. I was planning on slowly adding hard or RO water to the tank once I got the new fish. So how does soft water effect them?