What scale am i supposed to use for a blue labs ec/tds pen, 500 or 700 scale numbers are considerably higher with the 700 scale. This is for when I’m adding nutes to my tap water
Thanx for any help
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Use the 500 scale Growmie, great TDS pen 
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Thank you that puts my mind at ease, numbers are much higher with the 700 scale so to be safe i diluted my mix with some more tap water yesterday so i wouldn’t toast my plants 
. Whats the 700 scale used for?
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700 scale is used in other parts of the world…not exactly sure of where
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England, Canada and Australia IIRC. It’s based on Potassium Chloride instead of Sodium Chloride.
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Appreciate that info
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Awesome thanx😊, at least this gives me numbers to go with. So all tds tells me is that the plant is taking up nutrients and if it isn’t its probably a ph issue . Is this a correct assumption?
Once the medium’s baseline numbers are established, runoff numbers are monitored going forward. Runoff is compared to the feed ppm and the baseline. By making these comparisons you know if the plant is taking up what is given to it. Also how much it is accumulating when compared to the baseline. If runoff ppm goes up it means the plant isn’t using it all. This can be either because it is more than it needs or something like ph is preventing uptake.
Young plants need less. Slow growing plants need less. Cold temps slows a plant down.
I found this article to be helpful
growweed easy also has great information and articles
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Sweet, thanx so much for the help😁
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