Starting out.

I was wondering where my ppm should be for seedlings. I've read 250 or so. My water is at 200 out of the tap. I've also read that these are unusable salts. What should I do? Thanks ahead of time for any help.

PPM for Hanna Chart PPM


Seedlings, Early Sprouts 100 to 250

Early Vegging 300 to 400

Full Vegetation 450 to 700

Early Blooming 750 to 950

Full Mature Blooms 1000 to 1600

Note: EC Calculations are different, here's a conversion chart :
heres a great chart that shows how different PPM can be from meter to meter... EC is the only real universal language...

So my tap is already 200ppm, should I add nutrients?