# Ca calculation?



## Laith (Sep 4, 2004)

I want to add Ca to my tank and the Fertilator says that 28g of CaCl2 will give me almost 26mg/l in 175 liter of water...

Is this right? My calculation is based on 36% of CaCl2 being Calcium. Therefore 28g of CaCl2 gives just over 10g of Ca. 10g of Ca in 175 liters is not 26mg/l...

What am I doing wrong? :???:


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## discus (Jul 20, 2004)

*Ca Calculation*

Hi Laith

Yeah something appears off. I tried redoing the calculation and this is what i get.

- If 100mg of a given chemical in 100 litres gives 1 ppm 
- then to get 1ppm in 175 liters then you would need 175mg of a given chemical per 175 liters
- I agree that CaCl2 contains 36.11% Calcium 
- Therefore 175mg devided by 36.11% equals 485mg or 4.85 grams of CaCl2

So according to my calculations 4.85 grams of CaCl2 in 175 liters of water will increase Ca by 1ppm

Do you agree? Can someone double check my calculations.

Discus


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## Laith (Sep 4, 2004)

You're off by 10...

485mg is 0.485g, not 4.85g.

Therefore 4.85g of CaCl2 will add about 10mg/l of Ca, not 1mg/l.

I think?


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## Edward (May 25, 2004)

*FAQ*

*gram / 100 l = 1 ppm*
CaCl2 Calcium chloride anhydrous 0.2769
CaCl2.2H2O Calcium chloride dehydrate 0.3668
CaCl2.6H2O Calcium chloride hex hydrate 0.5466

*gram / 175 l = 1 ppm*
CaCl2 Calcium chloride anhydrous 0.4846
CaCl2.2H2O Calcium chloride dehydrate 0.6419
CaCl2.6H2O Calcium chloride hex hydrate 0.9566

Edward


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## Laith (Sep 4, 2004)

Ok thanks for the clarification... lucky I double checked the Fertilator calculation before pouring in all that CaCl2! :smile: 

So I added 12g of CaCl2 which I calculate gives me a concentration of almost 25mgl/l in 175liters of water.

Am I right in calculating that 25mg/l in 175 liters of water will raise the GH by about 3.5 (25 * 2.5 / 17.86)?


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## Edward (May 25, 2004)

Correct, if you have the right Calcium chloride.

Edward


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## Laith (Sep 4, 2004)

Ok, many thanks!


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## discus (Jul 20, 2004)

sorry 

Didnt have my calculator handy ;-)


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