Using jacks 321 with ro water

Hey everybody i had a question with using jacks 321 in ro water when starting ppm is around 10 to 15 ppm i add full strength of part a,b. And espon salt i get around 550 ppm im in the first week of flower and i begin to notice lower leaves begin to yellow and crisp do yall add more part a to increase ppm and runoff is showing around 600 ppm with ph at 5.8 im in 70/30 coco please and thank you!

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I run 18, 12 and 6 grams each of the three parts using 130 ppm tap and my numbers come out around 1,100 ppm. I suspect either your mix ratio is off or you have a broke meter.

Lower leaves will yellow and die during flower: perfectly normal.

Pictures would help a bunch.


@Myfriendis410 it could be my meter ive only had it for like a month and it has been consistently reading those measurement im try and pick up and new one today and see if the reading are similar and will get back to you thank you

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That sure sounds like a glitch. I never get consistent readings.

To how much water?

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@antonioperez96 I was under the impression that r/o water was neutral and would misread when ph-ing and whatnot. Adding up and down just makes things even funkier from there. Maybe that has something to do with the situation?

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Per gallon

Yes. PPM measurements under 50 or 100 really aren’t reliable and should be ignored.

In coco? I’m a soil grower and keep my runoff near 1,000 by feeding the Jack’s recommended dose, and only the dose. I use the 4.0/2.5/1.2 no matter how many gallons I feed. Maybe I need to step it up and push the nutes a bit harder.

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18 grams A, 12g part B and 6g epsom ? Is that right? I do

3.7 grams Part A
2.5grams Part B
1.1 grams of Epsom salts and get slightly under 1000 ppm.

And i was thinking of going up to 1500 ppm. How high is yours with those amounts.

Apologies for all the questions. Trying to dial in my nutrients strength

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We’ve got the same questions.

I just checked my bags of Jack’s. They say 4.0 and 2.5. I’m not sure about Epsom. I think I remember adding 1.2 each watering. It’s been October of last year since I’ve fed a flowering plant, so my memory is shaky.

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This is directly from their site. Hence the name 3 2 1 is the amounts. Where did you get 4 from? @MidwestGuy even though the couple of milligrams aren’t going to hurt them any.

I see what you mean now. I never looked at label i just went from what they posted on their website. Thanks.

I bought this bag around October of last year.

Step it up some. I don’t know much i’m really new to all this but from what i hear is a good place to be is around 1500 ppm is from what I’ve been advised.
My next feed will be stepped up as well. Good luck!
I still want to know about those rather large numbers posted by the moderator

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I’m running 18 12 6 per gallon, base water is 130 ppm and I add silica. TDS comes out to around 1,100 ppm and plants are happy. I’d be uncomfortable up around 1,500 ppm myself.

You can always mix your nutes then dilute with water to hit desired TDS.


What is a good ec/p meter? Other thsn bluelab long story ob why i stay away from them.

Correction: 1,200 ppm on the nose. Plants are gorgeous.

I went through 3 Apera PH meters before investing in a Bluelab. In use for 3 years and calibration is still spot on. I can get a replaceable PH probe from my local grow store too.

Here’s my four juveniles lol:

Can you please break that down so i can understand. I have not a single clue of you you mean when you say 18 12 6. What are they,18 of what per gallon. 12 of what per gallon. Are you speaking of grams? And also grams of what part a? I’m not even 2 mths in on this journey so i’m learning every chance it get! Highly appreciate your time. Thx! And i would love to be at 1200. Sounds ideal.

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