# Ca:Mg dosing



## Erirku (Oct 5, 2004)

So this is what I got from the fertilator:
7tsp=19.91ppm of Ca
2.5g=5.13 ppm of Mg
Do I just dose this amount into the tank?
Also, I did one from Chuck Gadd's calculator, and got a totally different dosing for only Mg, don't know why he hasn't updates and put in a Ca one?!
Heres what I got from it:
9Tbsps in 250ml of water gives me 1.02ppm per ml.
So I did a check on the fertilator and it gave me this:
9Tbsps=27tsps=55.38ppm in 15G
Can anyone tell me whos wrong or what wrong? Thanks


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## defdac (May 10, 2004)

Very good question. I'm confused about this too.

I'm dosing in my 310-litres tank based on Fertilator: 
10 ppm Ca from CaCl2 (19.23 grams, roughly 4 tsp CaCl2)
2.5 ppm Mg from MgSO4 (6.65 grams, roughly 1 tsp MgSO4) 

..each full-dose when I see less pearling from plants.


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## Laith (Sep 4, 2004)

The Ca calculation (using CaCl2) in the fertilator is wrong.

I almost used it and then double checked my numbers. Otherwise I would have dosed a lot more Ca than I wanted to.

See this thread:

http://www.aquaticplantcentral.com/forumapc/showthread.php?t=4681


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## Erirku (Oct 5, 2004)

So what should I do?
Edward, please help me!!! Thanks


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## Edward (May 25, 2004)

Hi
This is why I created the FAQ in the Fertilizing Forum. Look for _* Maximum solubility, Chemical composition and g / 100 l -> 1 ppm*_ .

Ca ppm
*CaCl2 .2H2O 0.3668 gram / 100 liter = 1 ppm*

0.22008 gram / 60 l / 15 gall = 1 ppm
2.2008 gram / 60 l / 15 gall = 10 ppm
4.4016 gram / 60 l / 15 gall = 20 ppm

1.1004 gram / 300 l = 1 ppm
11.004 gram / 300 l = 10 ppm
22.008 gram / 300 l = 20 ppm

Mg ppm
*MgSO4	1.0141 gram / 100 liter = 1 ppm*

0.60846 gram / 60 l / 15 gall = 1 ppm

3.0423 gram / 300 l = 1 ppm

Note:
You can not dissolve 9 tbs MgSO4 in 250ml. See FAQ Maximum Solubility Table.

Edward


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## chiahead (Dec 18, 2004)

so if the fertilator CaCl is incorrect how would one add the correct amount? I am not too good at understanding the numbers here. I have an 80 g but I always see liters used. I went by the fertilator and added way too much CaCl last week, really hurt my plants. can I just use the fertilators calculations and multiply the result in ppm by 10? Thats what ur math looks like its off by.


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## Edward (May 25, 2004)

80 gall = 300 liters


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## discus (Jul 20, 2004)

Things seem to have come to a halt on this one. 
Is it clear for everyone?

Ask more questions.

Discus


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## defdac (May 10, 2004)

No, not to me.

I would like to read about the inner workings of wich ion balance Ca, SO4, K, Mg that is generally good to plants. Also this NO3-Ca-thing would be nice if some could break down a bit. P seems to compete with Ca also.

My water company recently dropped the GH to below 2 and the curling are gettnig worse.

Less PO4 (less growth-rate) and a more adquate gentle circulation seems to have improved things with my A. reineckii, but the L. glandulosa still shows twisted leaves.


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## Erirku (Oct 5, 2004)

Upon adding the fertilators dosing regimen, I have seen dramatic growth in my tank. My Rotala M. started to turn red and all the twisted and stunted new growth is being gone. On the other hand my A. gracillis and L. aromatica/L. Hipuhandres? is still growing stunted/twisted leaves?!!! So I have to do some more tests. Thanks Edward for the help and all who partake in the APC forums.


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## GillMan (Feb 22, 2005)

I started using CaCO3 to increase my calcium levels to obtain a 4:1 ratio of Ca:Mg. I got my new La Motte CaCO3 test kit this week and tested the water after a 70% water change, then, along with my GH value, calculated the ppm for Ca and Mg. I finally added back some CaCO3 to my tank to raise the Ca level to get to the target ratio. It was easier than I thought it would be.


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## Edward (May 25, 2004)

Dosing the dry *Discus Mix* and the *Mg Solution* to maintain Ca and Mg concentrations is easy. You can start testing Ca and Mg once a week and then adjusting the Mg daily dosing to maintain 1 - 5 ppm. For the Ca, one tsp per 75gall / 300l in few weeks time will do the trick. I keep the Ca between 20 - 30 ppm. These two elements are not being taken by plants as fast as NO3 and PO4 so keeping it in order is not difficult.

Edward


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## defdac (May 10, 2004)

Edward said:


> For the Ca, one tsp per 75gall / 300l in few weeks time will do the trick. I keep the Ca between 20 - 30 ppm. These two elements are not being taken by plants as fast as NO3 and PO4 so keeping it in order is not difficult.


I *think* this is part of the problem people have with Ca-deficiencies: Too fast growth due to perfect nutrient levels and high light.

Ca is easily outcompeted/displaced by other ions like Mg, K, P and thereby the Ca-deficiencies are easily triggered with relatively high PMDD-levels, perfect CO2 and high light.


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