# Adding calcium carbonate to freshwater aquarium.



## crayfish

Just wondering, would it be reasonable to add strait Calcium carbonate to harden the water of a freshwater aquarium.

I did some research and I can only calcium carbonate in relation to salt water reef tanks. From what I under stand adding it to those tank may actuall decrease the hardness of the water, because some of the salts in the water would combine with the less desolbable Calcium Carbonate.

But i can't find any thing on if you can use it in a Freshwater tank to rise the DH? Can you?


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## livebearer

if im not wrong calcium carbonate is aragonite, and i have a 29 salt water tank that has it in there and i had a 10 gallon sw tank with it also but after 3 mos i turned it to freshwater and left the aragonite in there. i dont really know how to read water perameters but i do have a ph kit and my water is at 7.6 good for livebears i believe but my kit is a basic on and doesnt go to 8 so that may effect the readings also.

dont know if i was any help but i can tell you i have live bearers and rainbows and 1 goldfish 1 puffer 1tetra and 1 bumble be cat fish and all is well i also have plants that are doing fine to. tanks been freshwater for 2mos now.


oh yea i know tanks way to over stocked *trying to curb my compulsion buying*


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## Rex Grigg

Calcium carbonate will raise both gH and kH. The drawback is it's almost insoluble. 

If you want to just raise kH use baking soda. If you want to raise gH then use Calcium chloride and Epsom salts.

All this info is contained in my Guide.


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## Betowess

Well, one can use crushed coral as a buffer to raise both GH (General Hardness) and KH (carbonate hardness) in a media bag in a canister filter. Many say it is too inaccurate, but it works for me. And the cost is nice at less than a dollar/lb.

And since I have zero GH in my tap water from a well (kind of a mountain underground spring) I add both calcium chloride and mg (epsom salts) like Rex suggested to raise the GH and baking soda to raise the KH. But one can't add them at the same time because a precipitate develops and the calcium chloride and Mg (Epsom salts) bond to make calcium sulfate which is very slow to dissolve. So I add them on separate days and it works fine. I also recommend reading Rex's valuble guide.


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## crayfish

Thanks!

One more thing though... where can you find calcium chloride? Is calcium chloride used as a De-icer? 

Thanks again!


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## Hoppy

http://www.gregwatson.com/DryAquaticFertilizers.asp is the best place to buy almost every chemical used in a planted tank. Cheap, good service, and good products.


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## Rex Grigg

Calcium chloride is a common de-icer. But many of them also contain salt. So be aware of that. I have found some brands that are pure CaCl2.


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## Betowess

There is a cheap calcium chloride product used for dehumidifiers that Lowes home stores sell called: Dri Z Air. The size is ~ 13 oz for about a dollar. Its 100% calcium chloride. No shipping charges for it if there's a Lowes near by.


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## crayfish

I just examined an unopened bag of de-icer that we have. It contains Sodium Chloride, Calcium Chloride, Magnesium Chloride, and Potassium Chloride. I know sodium, Calcium, and Magnesium are components in water hardening, and I am pretty sure Potassium is present in fertilizers. Would it be ok to use this? 

Also is it any problem that they are all chlorides? 

Thanks yet again for all your help!


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## splattered

livebearer said:


> if im not wrong calcium carbonate is aragonite, and i have a 29 salt water tank that has it in there and i had a 10 gallon sw tank with it also but after 3 mos i turned it to freshwater and left the aragonite in there. i dont really know how to read water perameters but i do have a ph kit and my water is at 7.6 good for livebears i believe but my kit is a basic on and doesnt go to 8 so that may effect the readings also.
> 
> dont know if i was any help but i can tell you i have live bearers and rainbows and 1 goldfish 1 puffer 1tetra and 1 bumble be cat fish and all is well i also have plants that are doing fine to. tanks been freshwater for 2mos now.
> 
> 
> oh yea i know tanks way to over stocked *trying to curb my compulsion buying*


No such thing as over-stocked. 
Do as thou wilt.

Sent from my SM-G730V using Tapatalk


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## mboley

crayfish said:


> Thanks!
> 
> One more thing though... where can you find calcium chloride? Is calcium chloride used as a De-icer?
> 
> Thanks again!


Kent Marine Turbo Calcium is pure calcium chloride

Sent from my SM-G900V using Tapatalk


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## jeffy

i just tried an experiment where i got some seashells (calcium carbonate) and ground them down in a mortar and pestle,then i got some water out of my tank in a soda stream bottle and lowered the ph to below 6 added three ice cubes with the seashell dust and then put it in the soda stream, gassed it up, then shook it up till no bubbles left . i then readjusted ph to 7 and was able to controll kh with the liquid. A 5ml test tube i was able to increase kh from 71.6 to 161.1 with .1 ml calcium liquid. three things i have read to dissolve calcium carbonate is 1. temp. ( colder it is faster it desolves) 2.acidity helps break the bond of the calcium carbonate and lastly co2 carbon dioxide helps to break it down in nature . Put these three things together you can liquify it.. it worked for me


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## Darkblade48

jeffy said:


> three things i have read to dissolve calcium carbonate is 1. temp. ( colder it is faster it desolves) 2.acidity helps break the bond of the calcium carbonate and lastly co2 carbon dioxide helps to break it down in nature . Put these three things together you can liquify it.. it worked for me


Hotter temperatures will aid in dissolution of substances, not colder temperatures. 

Technically speaking, acidity (of which carbon dioxide is slightly) will push the calcium carbonate equilibrium to the right, which aids in dissolution. It is not really 'breaking the bond' as you have put it.


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## Pwilly07

Does the Greg Watson guy still sell things? The link doesn't work anymore. Thanks!


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## Seattle_Aquarist

Hi @Pwilly07,

I believe that Greg Watson sold aquariumfertilizer.com in 2007 to Alan Kaufmann, currently Julia Adkins is running the business. I still purchase most of my fertilizers there, especially CSM+B. Why? Because Plantex CSM does not contain the boron (B), it has to be added (hopefully) by the seller and aquariumfertilizer.com knows how much to add from the original formulas by Greg Watson.


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## nel

Darkblade48 said:


> Hotter temperatures will aid in dissolution of substances, not colder temperatures.
> 
> Technically speaking, acidity (of which carbon dioxide is slightly) will push the calcium carbonate equilibrium to the right, which aids in dissolution. It is not really 'breaking the bond' as you have put it.



Fun fact, calcium carbonate works in the opposite way. In lower temperatures it dissolves better. Most substances dissolve better in higher temperatures, but not calcium carbonate.


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## Tiger15

Adding calcium carbonate or calcium chloride does not provide a balanced hardness plants need as it provides Ca only. Adding dolomite will provide both Ca and Mg carbonate, raise kH and gH, and buffer the pH at 7.6. It's equivalent to dosing gH buffer without dosing as it is in the substrate that adjust to dissolution rate according to pH. Lower pH will dissolve faster as you inject CO2, and slower or stop dissolving at higher pH. I use the following brand in my planted tank that I inherited from the days I kept African cichlids. I prefer dolomite to crushed coral because the grains are not dusty, less sharp, about 1-2 mm and dissolves slower.


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