# Dosing calcium carbonate



## KevinC (May 24, 2004)

Calcium carbonate is considered water insoluble - it dissolves very slowly. Put some in a filter bag and add it to the filter - it will dissolve slowly, adding to your GH and KH.

Kevin


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## Marc (Oct 13, 2004)

KevinC said:


> Calcium carbonate is considered water insoluble - it dissolves very slowly. Put some in a filter bag and add it to the filter - it will dissolve slowly, adding to your GH and KH.
> 
> Kevin


I didnt know it effected GH? I thought it was only KH that went up?
Baking soda works great also.

Marc


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## KevinC (May 24, 2004)

Marc said:


> I didnt know it effected GH? I thought it was only KH that went up?
> Baking soda works great also.
> 
> Marc


Calcium (and Magnesium) = GH
Bicarbonate (the carbonate grabs a hydrogen from the water) = KH

Baking soda = sodium bicarbonate

Kevin


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## jayrug (Oct 22, 2004)

Adding it to the filter doesn't seem very efficient to me because i need to add 4-6 teaspoons per water change. I really don't want to open the filter once a week if I don't have to. 

I actually added 5 teaspoons to a few gallons of water 24 hours ago to see if it would ever dissolve, so far it's not looking good. 

Is there an alternative that would be measurable weekly? How about just baking soda and epson salt? Although my java ferns seem to have a calcium deficiency. New growth is yellowish and somewhat deformed. 

Btw the calcium carbonate is finally starting to dissolve in my tank 4 days later. Stupid newbie mistakes.. That’s one I’ll never do again :icon_redf


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## Jacan (Apr 24, 2003)

Calciumcarbonate CaCO3 disolve in water with CO2 and H2O

CaCO3+H2O+CO2 <=> Ca2(HCO3)

1 teaspoon of calciumcarbonate = 2-3 g, and 1 dH = 1mg CaCO3/L, so 3 - 4 teaspoon is way to much for a few gallons


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## KevinC (May 24, 2004)

jayrug said:


> Adding it to the filter doesn't seem very efficient to me because i need to add 4-6 teaspoons per water change. I really don't want to open the filter once a week if I don't have to.
> 
> I actually added 5 teaspoons to a few gallons of water 24 hours ago to see if it would ever dissolve, so far it's not looking good.


As I said, it is considered insoluble - this means it dissolves VERY slowly. It doesn't matter how much you add each week - most of it probably won't dissolve for several days.

Let's start over - WHY do you need to add it? If you are trying to raise your KH, just use baking soda. If you are trying to raise your GH, WHY? If it is due to a definite calcium deficiency, you need calcium chloride (which is very water soluble) or a commercial calcium supplement (they sell them for saltwater tanks).


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## Buck (Oct 13, 2002)

jayrug said:


> Although my java ferns seem to have a calcium deficiency. New growth is yellowish and somewhat deformed.


 Have you checked your nitrate levels ? I doubt it is a calcium deficiency with the ferns unless all the plants are showing it, my ferns love soft water and I add no calcium.


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## jayrug (Oct 22, 2004)

> Let's start over - WHY do you need to add it? If you are trying to raise your KH, just use baking soda. If you are trying to raise your GH, WHY? If it is due to a definite calcium deficiency, you need calcium chloride (which is very water soluble) or a commercial calcium supplement (they sell them for saltwater tanks).


KH and GH out of my tap are both in between 2 and 3. It seems as it got colder both dropped one degree. Is that even possible? I'm using an aquarium pharmaceuticals test kit. Yesterday it only took 2 drops to change colors for both out of the tap. 2 months ago it took 3. I'm pretty sure the kit is still good because my tank now has a KH and GH of 4 after the calcium carbonate mess. After reading a lot about hardening water and a previous thread on here I thought that calcium carbonate would work for me. I bought the calcium magnesium carbonate (dolomitic) from Greg guessing that the water also needs magnesium. Again I'm new to this so it was just a guess. I was aware it would take a long time to dissolve but I didn't realize it was this bad. I bought 2 pounds of the stuff so I might as well use it. Today's water change day so I'm gonna put it in a filter bag this time. :icon_roll



> Have you checked your nitrate levels ? I doubt it is a calcium deficiency with the ferns unless all the plants are showing it, my ferns love soft water and I add no calcium.


Buck, the reason why I guessed it's a calcium deficiency is because I've had nitrates in between 10-15ppm for 3 weeks strong now. It could be an iron deficiency too though. I just started dosing iron chleate(5ml week) on top of Plantex CSM+B(15ml week) 2 weeks ago. Either way the java's showed no signs of improving.


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## Desolas (May 9, 2004)

> KH and GH out of my tap are both in between 2 and 3. It seems as it got colder both dropped one degree. Is that even possible?


It is, but more importantly are you testing your tap water when it's cold from the tap? If so, it might be your test kit reading wrong, they are calibrated for a specific temperature range. Too cold, or too hot, and it can be off.

It really is much easier to dose Calcium Chloride. It will be harder for you to get your GH adjusted using Calcium Carbonate, with CaCl it is much easier to measure the dry weight into a known quantity of water so you know the PPM of the dose bottle. You can then figure out exactly how much of the liquid CaCl to add to raise your tank water by the amount you want. Also CaCl is inexpensive, I think the last time I bought it I paid $5 for 2.2kg. So despite the fact you already bought the Calcium Carbonate it is not like it's an expensive mistake.

I also have to agree with Buck, I haven't used CaCl in my tank since I've had ferns and I've got pretty soft water, (GH 2) and the Java ferns have easily doubled in 3 months, and I've got a Bolbitus that's putting on mass like crazy. They seem more effected by nitrate, potassium, and iron IMO. All I fertilize with is a little bit of Kent Plant-Gro, which has all three.

One thing you could do, if your really stuck on using the Calcium Carbonate is premix some water for water changes and stop doing it straight from the tap. You can add the calcium to a 5-10g water container, with tap water and a powerhead until it breaks down, then change water with this premixed water, that way you don't have to wait for it to break down in the aquarium.


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