Need help with Jacks Concentrate

[RottyRzr]

I need some help with making and using a concentrate with Jacks 5-12-26. I believe I've thought about it so much that I've confused myself now and can't wrap my brain around figuring this out.
So I planned on making a 100x concentrate using Jacks. The 321 formula calls for 3.79 grams per gallon. If I want to make a gallon with 100 doses so I would add 379 grams to the gallon of water. Which brings me to my confusion. How many milliliters would I draw from this concentrate to dose a gallon of water to equal the 3.79 grams per gallon?
I know 1 gram = 1 milliliter of pure water but since there is 379 grams of fertilizer in that gallon now, the mass has changed so how do I figure out how many milliliters of concentrate to use per gallon of reservoir water?
Would I draw 3.79 ml of concentrate to add to 1 gallon of reservoir water?
Help me out. My brain is all tangled up now

 

[silver blue]

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[RottyRzr]

Folks usually rely on an EC meter to dose the plants. When you make your own liquid nutes you can make it any concentration within reason. The applied nutrient solution though is measured by the meters. You want a pH meter too for checking on that as well. If you are feeding the same amount every watering then you don't need to meter your solution. What I mean is that you will soon discover just how much pH down to use because the city water supply usually doesn't change too much. The ferts amount you will get a handle on as well once you know the values of what your concentrate does to the solution water.
If you get the meters (I like Apera) be sure to get the storage solution and observe the stability indicator (smiley face) before turning the meter off.
I use rubbingg alcohol to clean the probes once the black mold appears in the storage solution. It takes a while for the black mold to form and is the result of contamination. The meter will still work pretty much but it takes longer to get the readings and stabilization. After I clean it (a wooden skewer and alcohol), rinse and sterilize the cap. New storage solution and Wah-lah.

 

[thumper60]

Without breaking out the calculator you will be close to 1.2 oz of the concentrate to 1 gal of water.

 

[Ozumoz66]

If it's an American gallon, there are 3785ml. And you have 100 doses in that gallon, so it'd be about 38ml/gallon.

 

[RottyRzr]

If it's an American gallon, there are 3785ml. And you have 100 doses in that gallon, so it'd be about 38ml/gallon.

Thanks. This is what I was looking for.

 

[sureshot138]

i ran 321 for years mostly 1.5 1 .5 with tap ph'd around 6. now i run the 15-05-20 with tap at 2g a gallon in veg, they love it.