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Thread: PPM of tap water

  1. #1

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    Default PPM of tap water

    FIrst DWC grow. CNS17 brand grow nute only gives ml/gal guidance. My tap water reads almost 300 ppm. Preparing first feeding/refill I got about 800 ppm. So I added about 500 ppm of nutes to the tap water is how I am figuring it (800 minus 300 baseline = net 500 ppm). 500 may be a bit too high for a two week old seedling ( that still isn't showing any roots). Should I use some distilled in future changes, use some sort of filter on the tap water, "adjust" for background ppm, or something else? Thanks in advance.
    Last edited by maters; 22-02-19 at 11:21 PM. Reason: grammer, addition for clarity

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    Which PPM scale are you using? - there are several, here are some of the most used....

    It's Not What You Know, It's What You Can Prove

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    Just use ec if you can it’s a whole lot easier
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    My JTD (inexpensive) meter only reports PPM. I have researched the EC issue a bit but either system should be convertible. My nute container does NOT list directions in EC units so that will not help me. Should I restate my questions in another way?

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    Quote Originally Posted by maters View Post
    My JTD (inexpensive) meter only reports PPM. I have researched the EC issue a bit but either system should be convertible. My nute container does NOT list directions in EC units so that will not help me. Should I restate my questions in another way?
    Whilst EC is easier, I'll work in PPM with you

    However, as I originally stated, there are different ways of measuring PPM So I need to know which PPM scale your meter uses...

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    Quote Originally Posted by M_C View Post
    Whilst EC is easier, I'll work in PPM with you

    However, as I originally stated, there are different ways of measuring PPM So I need to know which PPM scale your meter uses...
    Thanks for responding!
    "JTD" is the only information I have on the meter. My underlying question is about adjusting for dissolved solids in the tap water. The specifics of how much to adjust (if any at all) is secondary.

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    Some people ignore their background EC/ ppm if it low, and they do fine.
    I didn't my tap water is 0.6 EC so I would be very careful to not over use any boosters or enzymes, I have bought a lot of bottled water for seedlings over the years. I bought a RO system 5 years ago and have never looked back.
    Tap water contains dissolved mineral solids e.g calcium, magnesium, sodium and nitrates also additives like fluoride, chloramine and chlorine. Some of these can be absorbed /transported by the plant and some cant.
    So there will be some excess nutrition possibly leading to over feeding or there will be more lock out issues from all that free radical Cal & Mag because it is mostly not in a readily available form like Cal-mag supplement which is chelated and standardised by mole weight and so on. Its just too big and attracts the smaller molecules that your plant can actually absorb like a magnet leading to deficiency's.
    Try and get yourself a decent EC/PPM meter or truncheon. Then you can be sure about what scale your using as M_C pointed out and then use the simple EC scale as REDDISIEL, M_C and myself advise, then you can follow a DWC grow diary on here without doing any conversions.
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    My background tap water is 0.2 ec (gone up from 0 for some reason). I started RDWC and made my nutrients up adding the tap water ec on top of the recomended, so recomended was 0.8 I would be feeding 1.0. Bad move was feeding far to high especially if you go over even a little bit and think "oh it will be ok".
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