I'm not sure where you are based and it looks like JayC has you well covered! As JayC says don't mess about with the parameters too much until the tank has finished cycling, then you can get on with altering the parameters. Your water is quite good (hopefully no chlorine etc though) so I would think you can just raise the parameters using your water and adding some standard GH/KH+ shrimp mineraliser. I add gh/kh+ to dechlorinated tap water for my Betta tank!
IF that doesn't work (but I am sure it should work fine) you can just buy a zerowater water filter jug to get RO equivalent water. That filter in the jug should last you very well as it is only removing 40ish TDS from your water.
NeoCaridina ideal parameters, PH 6.5-7.5, TDS 150-250, GH 6-8, KH 1-4 and I think this should be attainable with your water plus gh/kh+, but these figures are ideal and a guide! The gh/kh+ is pre-set to produce these ideal figures/proportions when used with RO water.