ppm of tap water - whats tolerable?

[herbie the love bud]

I am still trying to figure out PPM of what?? Chlorine?? Bromine?? Sodium Chloride?? Fecal Solids?? what?? I don't understand "TDS levels".

Not sure if that was a question or just rhetorical. Yup, you're right. PPM of tap water doesn't mean shit. Doesn't have sticker on the water with "Guaranteed Analysis".

[Mississippi Steve]

Not sure if that was a question or just rhetorical. Yup, you're right. PPM of tap water doesn't mean shit. Doesn't have sticker on the water with "Guaranteed Analysis".

Actually it was a question...having a little chemistry background, and playing around with my own grow, I would like to know what they are talking about.

BTW there are test strips that are available for aquarium water that will give you levels of a dozen chemicals and minerals for just a couple of bucks.

[gainesvillegreen]

Actually it was a question...having a little chemistry background, and playing around with my own grow, I would like to know what they are talking about.

BTW there are test strips that are available for aquarium water that will give you levels of a dozen chemicals and minerals for just a couple of bucks.

Wikipedia - T.D.S.

TDS is Total Dissolved Solids, or the measurement of ions and some other substances dissolved in the water. This is a measurement of the ions/salts in a soution. In your setup, this is basically measuring the amount of fertilizer/material in your water that your plant can/will absorb.

Quote from wiki: "The most common chemical constituents are calcium, phosphates, nitrates, sodium, potassium and chloride."

See the most common constituents? Notice the nitrates for N supply, phosphates for P, and potassium for K? Calcium and magnesium are also fairly common in this application, especially in 'harder' waters.