reverse osmosis system

Hi all, I'm seriously debating on whether or not I should get myself a R/O filter and eliminate the headaches caused by my 280ppm tap water. I'm fighting a magnesium deficiency due to all the calcium in me water, but it's not going well... and I'm fed up. I was wondering if I have everything...

Ok so my water had a PPM of like 325 and after the Reverse Osmosis System it is around 42-50 Should I mess with it some more or be satisfied? I mean I want a 0 ppm but 45 ppm is a heck of a lot better than 325! In this video he takes 320 PPM to 0 wtf???? I have the 200 model which is better...