~200 ppm is fine. Nowhere near a level that causes a problem.
It won't impact much. you may need more/less of something compared to another garden.
if going soilless/hydro, your nutes 'should' ph-balance and hopefully buffer the solution too. if you are going with soil, you'll want some 5% white distilled vinegar handy. Get some cheap 3-5mL pipettes for easy ph-balancing after nutes added. 100pack of ph-strips (4-color code for easy reading) will be enough to work things out. if it takes 2mL it will continue to take 2mL unless your tap or nute formula changes. you won't need many after that except for spot checking.
i have 300ppm hard water. I still needed 100+ ppm of Ca and 75-80ppm of Mg (elemental ppm, not ug/L) from my fertilizer.
hell, i use 'soft' water now and i didn't have to change levels of my Ca or Mg.
Magnesium = Mg, not Ma, just in case.