I don't see why you're talking about raising the hardness or PH, you haven't mentioned the PH, but kribs like the water a bit acidic and soft, they're NOT african lake cichlids like, say, an electric yellow. They're from the rivers in africa, water wise they'd go better with your average south american cichlids than the lake cichlids.
I'd say throw them in the new tank, seed it from your other tank to get the bacteria jump started. They're tiny fish, probably wouldn't even get the ammonia levels up to a detectable range before the tank cycled.