You should be fine. I'm on a well and have really hard water ranging from 450 to 650 ppm (25 to 40 dGH). It's on the upper range of that level except for a couple of months in the spring during the snow melt and run off. I have kept neons for a full normal lifespan of 5 years or so. I know they'll never spawn, but otherwise they stay fully colored, eat well, and behave normally.
WYite
WYite