# which are good levels for calcium/magnesium in freshwater?



## blondy33 (Jan 13, 2007)

hey can anyone tell me the good level of calcium/ magnesium in freshwater?
i could not find any test to meassure them but i know that 1GH its 20ppm of calcium/magnesium.
please let me know the low / high level range of it.


----------



## John N. (Dec 11, 2005)

I don't know specifically what the optimum levels of Ca/Mg are, but in most cases when the GH is between 3-8 degrees your good. My GH is around 8/9. Plants grow fine.

-John N.


----------



## Salt (Apr 5, 2005)

Edward has posted a lot of evidence from his own testing that it's best to keep magnesium levels below 10 ppm actual magnesium (41 ppm as CaCO3). Some plants stunt in higher levels than that. I've also read posts in the past from people who get shrimp die offs after dosing MgSO4.

Calcium levels tend to be OK at higher levels. I personally do about 45 ppm as CaCO3. "Leaner is better" seems to be an emerging trend... lately, I try to keep my TDS below 300 µS.


----------



## yxberia (Apr 19, 2005)

I believe there isn't any. Because the level is plant-dependant.


----------



## blondy33 (Jan 13, 2007)

hello
John my GH its 11-12


----------



## azfishguy (Jul 1, 2005)

The liquid rock that comes out of my tap has a Gh around 17 and Kh not much lower. I can still grow some species of plants in it with good lights and adjusted ferts. Some grow fine some struggle and others don't grow at all. I currently use only RO water with Gh=3 and have great results even with the so called "difficult" plants. IME plants grow better in softer water hands down.


----------

