This site is supported by the advertisements on it, please disable your AdBlocker so we can continue to provide you with the quality content you expect.
  1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.
  2. Unfortunately for Photobucket users, things have changed in a big way as of June 26th they are rolling out a $399 per year subscription fee for those who want to hotlink images from Photobucket’s servers to display elsewhere.
    This does not mean it only affects this site, It now means that billions of images across the Web now display an error message instead of the image in question. :(
    Dismiss Notice

Gh & Kh Issues

Discussion in 'General Plant Topics' started by jerime, Feb 26, 2007.

  1. jerime

    jerime Expired Subscriber

    Jan 23, 2005
    Likes Received:
    In the past, everybody thought high GH & KH are not good for many delicate plants, thus we all s'd maintain low KH & GH.
    Then we understood that the real problem is with KH mainly.
    What is the problem with high KH (if there's one)?
    Why do you (TOM) mention here from time to time that high GH is even betterr for plants?
  2. Tom Barr

    Tom Barr Founder
    Staff Member Administrator Social Group Admin

    Jan 23, 2005
    Likes Received:
    One, the GH is basically 2 plant nutrients, Ca and Mg.
    KH is not.

    KH, or alkalinity determines pH. We artificially lower pH with CO2 gas, tannins etc, so pH in and of it's self is not critical, nor the real player here.

    KH is.

    This can and does influence uptake of various nutrients, some plant's enzymes are optimized at lower pH's(think KH though!!).

    It's not just CO2 uptake that will help these plants, you have to make sure it's the KH.

    Most plants are fine at high KH's, their enzymes are okay with the higher alk levels transporting nutrients in/out etc.

    All plants are fine at low KH's on the other hand.
    Thus in aquatic systems, KH, rather than pH is the real player in uptake preferences.

    Note: traces in general are more available at lower KH's, while macro nutrients are more available at moderate to hard water(KH here, not GH)

    GH is what folks remove when they soft their water with salt, the KH is very high, but very low GH.

    Tom Barr

    Tom Barr
  3. kazooless

    kazooless Junior Poster

    Sep 24, 2006
    Likes Received:
    So, what's a high KH?

    So, how high is too high for KH? Here in SD, it appears I have a KH of 7 in my aquarium. I didn't care about it since I'm using a drop checker to measure my CO2.


Share This Page