Per my water company, total hardness as CaCO3 averages 107ppm (roughly 6 dGH using a conversion factor of 17.86 per http://www.thekrib.com/Plants/CO2/ha...arryfrank.html). A spot check at the LFS indicated roughly 2.5 dKH. The water changed color on the second drop, but was not clearly either color until the third drop.
I had inferred that this would provide enough minerals for the shrimp, while remaining soft enough for many fish species. The Boraras in particular I'm not certain.
Another problem that I have with water parameters is pH. The city alkalinizes the water to protect pipes. It comes out of the tap around 9.5 and sits around 8.2 in the aquarium. I plan to start aging my aquarium water in peat, hopefully to make it just below 8.
The GH at 6 is OK for Boraras. I will let the shrimp experts comment on shrimp in this soft water as I've no experience. As for the pH, I would agree with lowering that. Your KH is not high, so this should not be too difficult.