RO system question please help

So i have been having issues with my water so i purchased a stealth RO 100. Before the RO system my water was around 8.0 and 280 ppm now after running it through its 4.5 and 0 ppm should i be concerned? is something wrong I was expecting the PH to be 7.0 anyone ever heard of this?

dude! lol I was told to never add ph up but you gotta do what ya gotta do to get your ph rite.. 0 ppm sounds awesome tho..

Umm I'd be scared drinking water with a Ph of 4.5. Are you sure your calibration meter is OK?