Hardness Ingredients

[ctyank]

The inexpensive product we use to increase KH is baking soda (NaHCO3 - Sodium Bicarbinate).

The inexpensive product we use to raise GH and add Calcium is Calcium Chloride (CaCl)*.

It seems to me the better product to accomplish both goals would be Calcium Carbonate (CaCO3). Using the others unnecessarily increases sodium content and chlorine content, no?

I'm guessing that the reason we do this because easily dissolvable CaCO3 is not readily available.

Do I have that right? Or can I get a powder form of CaCO3 pretty easily?



* I know I excluded Epson Salts (MgSO4).

[MrGoodbytes]

Calcium carbonate is a major component in animal skeletons. You can add CaCO3 to your aquarium with crushed coral gravel, coral sand, or coral skeletons, but they may look out of place in a planted aquarium. It is not necessary to add a lot either.

Calcium carbonate also occurs in dolomite, which is pretty common, at least around here.

Graeme

[ctyank]

Crushed coral takes way too long to dissolve. Are there forms of CaCO3 that dissolve quickly?

Also, does anyone have an opinion about the extra Sodium added to the tank from the Sodium Bicarbinate or the Chloride added from the Calcium Chloride?

[MrGoodbytes]

I'm quite sure calcium carbonate has a low solubility (>1mol/L), so assuming this, there is no quick way to dissolve it in water.

Carbonates of Group 1 elements (Sodium, Potassium, etc) have a higher solubility. I'm not sure where you can get K2CO3 potassium carbonate), but you could try NaHCO3 (sodium bicarbonate). I have read that plants prefer low quantities of sodium, so the coral may be your best option.

Please let me know if I have made any mistakes,

Graeme

[djlen]

What's the rush on the dissolving of the crushed coral?
I lasts for months and does a great job of raising kH.
Put a bag of it into your filter and you'll start to see your kH rise in about a week or so. It's not fast acting but it works well.

Len

[superjohnny]

I dissolve about 1/8tsp of calcium carbonate in a jar of water and add that to my tank after each water-change. It turns the tank cloudy for about an hour or two, but dissolves completely.

Leaving crushed coral in your filter will slowly, but continually raise your GH/KH so after a water change your water won't be as hard as after a week or so. If you are adding a constant source of CO2 (like pressurized) this will cause your PH to decrease as your hardness increases. For this reason I add calcium carbonate instead of crushed coral in the filter... because it keeps my PH more stable.

Just my experience.