# Using calcium chloride(CaCl2) to increase the gh level?



## Yue (May 28, 2010)

Hi, all,
I've read a lot of articles about using calcium chloride to raise gh. My big concern is that I think it will release chloride gas which is harmful to fish. (that is one of the reasons why we want to use water conditioner before water changes to get rid of chloride in the tap water.) But it seems like no one really talks about this. I wonder whether it bothers?

Any one knows about this?

I have two tanks. Both of them have very low ph (6.2, 6.5). For the two tanks, GH and KH are both close to 0. I've been thinking to raise them. Now after reading quite a lot of materials and seeing a lot of ways to do so people are talking about, I think calcium chloride and baking soda are good for my tank, as I don't want to raise the ph too much (I am keeping treta fish which likes soft water more). I read using CaNO3 will raise ph dramatically. I've been thinking about coral too, but it's kinda less worthy to buying it as I just need so few (maybe 1-2 cups according to an artical I read).

Any suggestions? 
Thank you all in advance.


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## Seattle_Aquarist (Mar 7, 2008)

Hi Yue,

Calcium chloride can be used to help raise dGH hardness, as can magnesium sulfate (Epson Salt). Actually, they are typically both used, usually in a ratio 3:1 or 4:1. Calcium chloride wiill release calcium and chloride into the water. Chloride is one of the micronutrients that plants actually need to grow.

I think you are concerned about chlorine (gas or liquid) which is not the same as chloride. A lot of people add another chloride to their aquariums, although typically not planted aquariums......sodium chloride (salt).


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## Nymsley (Mar 24, 2009)

I think you are saying chloride and chlorine are the same thing but they aren't. Chlorine, Cl2, is added to tap water and is a strong oxidizing agent which harms bacteria and fish amongst other organisms. Dechlorinators reduce the chlorine to chloride, Cl¯, which is not toxic under normal conditions.

(Oops, didn't see when Roy slipped in there.)


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## Yue (May 28, 2010)

Thanks. Seattle_Aquarist and Nymsley.
I am clear now.


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## HeyPK (Jan 23, 2004)

See Erik Olson's explanation of KH and GH in The Krib:
http://www.thekrib.com/Plants/CO2/khgh.html

CaCl2 will increase KH, but not GH. You don't have to worry about it producing chlorine gas. The chloride ion is very stable.

I have peculiar tap water that has zero KH, but a GH of 9. That is because it has no measurable (with my test kits) calcium or magnesium, but a lot of sodium bicarbonate in it.


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## Elohim_Meth (Nov 4, 2007)

HeyPK said:


> See Erik Olson's explanation of KH and GH in The Krib:
> http://www.thekrib.com/Plants/CO2/khgh.html
> 
> CaCl2 will increase KH, but not GH.


It must be mistake, this cannot be true. That article doesn't even mention CaCl2. 


HeyPK said:


> I have peculiar tap water that has zero KH, but a GH of 9. That is because it has no measurable (with my test kits) calcium or magnesium, but a lot of sodium bicarbonate in it.


That were the case if you had, on the contrary, kH 9 and GH 0.


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## HeyPK (Jan 23, 2004)

OOPS! my mistake. I got the two mixed up. 

Ca Cl2 increases GH, not KH, and my tap water has a KH of 9 and a GH of 0. 

Anyway, you don't have to worry about chlorine gas.


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## Seattle_Aquarist (Mar 7, 2008)

Hi All,

Actually that article on The Krib was written by Geoge Booth, not Erik Olson. Elohim_Meth is correct, the article does not mention CaCl2, it does discuss CaCO3 (calcium carbonate). Both have the effect of raising the calcium level and effecting the dGH. Calcium carbonate would also add carbonate ions and increase the dKH as well. Sodium bicarbonate (NaHCO3) will raise the dKH but not the dGH.


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## Diana K (Dec 20, 2007)

Back to the original question:
I use Seachem Equilibrium to raise the GH in several tanks. This has other minerals, not just Ca and Mg. 
If you want to use just Ca and Mg, then use both, in a 3:1 or 4:1 ratio as noted above. You may have to do some chemistry math to figure out which materials and how much of each to use. Plants and fish need both Ca and Mg. Adding just calcium or just magnesium might make your GH test turn the right color, but does not supply the minerals the fish and plants need. 

To raise the KH I add baking soda. 1 teaspoon of baking soda will raise the KH in a 29 gallon tank by 2 degrees. In this tank the KH was 0, and the pH was 6.0. The pH came up to 6.2. 

By adding these materials slowly, in small amounts you can gradually alter the water parameters until you have the GH and KH just where you want it. When you do water changes be sure to test the tank and make up replacement water that matches. If you are doing a reduced water change system, then test the water occasionally. Fish, plants and microorganisms all remove these minerals from the water, and you may need to replace them occasionally. 

Many plants thrive when the KH and GH are at least 3 degrees, and higher is fine for the plants. For the fish that like soft water 3 degrees is great for most of them. 

If you are aiming for a hard water tank (Rift Lake fish, livebearers, certain Rainbow Fish and others) then a GH and KH over 9 degrees would be better. I do this with the same materials, and also have coral sand on the floor of these tanks.


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## Seattle_Aquarist (Mar 7, 2008)

Hi Diana K,

Actually I agree with you. I used to do the CaCl2 and MgSO4 but getting the proportions correct was always a pain. For the last six months or so I have been using Seachem Equilibrium and it is much easier and more balanced.


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## Newt (Apr 1, 2004)

I have six 16oz bottles of ElectroRight I could sell you for $35 shipped.
PM me if interested.


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