does the ppm im supposed to be account for tap water or is it for r/o water?

[stew_smith]

on my first grow doing a dwc. my question is when i read to have the ppm around 800- 1000 is that on r/o or tap water?
r/o or distilled being 0-2ppm so that would be 800-1000ppm of nutrients and what ever else is added to the system.
my tap water is a high, a little over 400ppm. (my town uses chlorine so i can eveporat that out over couple days or use a brita) so would i only be adding 400ppm of nutrients to get to the 800 or 1000 mark, or would i want to add the 800 or 1000 and get 1200-1800ppm mark?

ive never seen this talked about before and i have looked around. my gut says to stay under a 1000ppm.

im looking into getting a zero water 5gal filter system but for now im just useing the tap water.

plants are 2 weeks old and doing well so far on it.

let me know what you guys think.

thanks
ss

[Green75]

Not to many people just go by ppm...it's more...% of nutrients full dose...or full dose...example...I own probly the best ppm meter there is...never use it...

[9fingerleafs]

Ppm is just an unit to talk about Electro Conductivity or EC. How well electricity goes trough depending on minerals and total dissolved solids in the water.

[9fingerleafs]

And to answer your question better look at it like this. My water is really hard. 750ppm hard. So I can only add about 500ppm of nutes before I saturate the water. But using RO water or destiles water with only a few ppm then you can add exactly what the plants needs instead of just giving random salts or too much calcium magnesium and even sodium. Plants don't even use sodium and tap water is usually treated with it. So if you can only give water with 1000ppm its better if they are 1000ppm of nutrients that you added than 1000ppm of pollutants that the plant cannot use