Question about DWC + hard water ppm

[Kegdas216]

Hello there. I have a question about hydroponics. I usually grow my plants organically, but I’m trying out deep water culture (DWC) during the colder months.
My tap water has a PPM of 150, and my nutrient feed schedule recommends 250-300 PPM for early growth. Should I add the recommended PPM to my water’s current PPM (for a total of 400-450 PPM), or should I subtract the PPM in my tap water from the recommended PPM (250-300 minus 150)?
I would greatly appreciate your help in understanding this. Thank you for your time and consideration. It’s the only variable I’m having an issue finding a definitive answer to.

 

[DillyTrying2Learn]

I use RO water, but if I were using tap water, I would let it sit for 24hr with air in it for the chlorine to evaporate from the water and then I would add my nutrients as if it was 0 PPM at the start. You have no idea what those 150 PPM'S are in your water and they may be stuff your plant can't even take up.Once again I don't have experience with tap water but if it was what I was running this is what I would try.

 

[budjamesbud]

Your city should have a water quality report you can find online. 130 isn’t bad actually, but who knows what it is

What I’ve read is you would subtract the city ppm from your desired final ppm. … or

Desired ppm = city ppm + nute ppm

I buy distilled water which starts at zero. I don’t have a big setup so the cost is minimal