The Lounge : Growers Round Table Discussion Thread

[jwcgarden]

Hi so I have a question about mixing salts by weight or ppm. Using Jacks for example plugging into a nute calculator. 3.6 grams part A and 2.4 B gives 660 ppm total. 448 for part A, 212 for B.

Now looking back through notes mixing by ppm meter for 600ppm total would be 360 A and 240 B.

Doing my own testing in my tap water starting at 80ppm. Adding 3.6 A brought me to 590ppm. Then adding 2.4 B brought me to 920 total. 590-80=510ppm of A. 920-590=330 of B.

How does this even make sense? I thought dry nutes absorb moisture, and would therefor skew my results making me use more nutes to achieve same ppm. According to the nute calculator Im using 4.1 of A to get 510ppm and 3.75 of B for 331ppm. Using 2 different scales to weigh nutes, could both scales be off half a gram? Should I mix nutes according to ppm instead of weight?

 

[jidoka]

No matter what you think your meter does not measure actual ppm. It measures EC and then makes a calculation based on salts you are not using.

One meter uses NaCl, another uses KCl and others who the fuck knows. Do yourself a favor and set your meter to EC.

If you must look deeper google salt index and ppm or EC or something like that

 

[jwcgarden]

No matter what you think your meter does not measure actual ppm. It measures EC and then makes a calculation based on salts you are not using.

One meter uses NaCl, another uses KCl and others who the fuck knows. Do yourself a favor and set your meter to EC.

If you must look deeper google salt index and ppm or EC or something like that

Perfect explanation I love how simple you put it!! Was getting confused and was thinking I was adding alot more nitrogen then the target 140 I was going for.

 

[jidoka]

If your entire N content comes from CaNO3 then you need 3.4 gm/ gal.

 

[jwcgarden]

If your entire N content comes from CaNO3 then you need 3.4 gm/ gal.

Atm am currently using Jack's at 3g per gallon and Calnit at 2.5. Comes out to 141n of the top of my head