My city water tests at 170 ppm for hardness (Ca/Mg). Any need for a CalMag supplement?

Discussion in 'Hydroponic Growing' started by corrd1312, Apr 20, 2021.

  1. Title pretty much lays it out. At 170 ppm out of the tap, will I need to add CalMag, or nah?

    It's an RDWC system, running Flora trio + Hydroguard.
     
  2. yeh that's about what mine is and I still need calmag.
     
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  3. Good to know. How much are you running?
     
  4. I use 2 ml per gallon.
     
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  5. 4 plants. 8 gal buckets + res, although they obviously aren't full. 35 gal, give or take? Might be closer to 30 gal.
     
  6. 170ppm just for Mg and Ca?
     
  7. Do these posts nest like old usenet? Shit. I tried to delete my idiotic post above, but all I found were markup options. I'm probably just making things worse right now.
     
  8. Yes, that's the hardness report as of last September. There may be other trace elements in there, but it's in there from limestone runoff. 99.5% calcium and magnesium.
     
  9. Hmm.
    Well, according to; Magnesium: Part of a Balanced Cannabis Diet
    “Concentrations of 25 to 50 ppm Mg are often available and provide adequate levels for plant growth for most plant species.” Apr. 24, 2019

    can’t find info for Ca

    also if you are growing in coco Ca/Mg is easily leached and using a bit of CalMag won’t hurt
     
  10. #10 corrd1312, Apr 20, 2021
    Last edited: Apr 20, 2021
    Hmm. Cool!

    For my case, I think the water is gonna be fine - the reason it's a bit hard is because it runs off of limestone (which is largely calcium).

    If it turns out the grow clearly needs it, then I'll go get some. If it don't, though ... great. Saved some $.
     
  11. Oh if you don’t already have calmag then no special need. If you already had some you could have used a bit.
    And yes limestone is heavily calcium.
    Just wondering, what does your pH come from the tap?
     

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