# Ca : Mg ratios and pale new growth



## Edward (May 25, 2004)

There are situations where people are trying to resolve pale new growth by increasing TE trace elements, iron, NO3, K etc. without success.
The actual reason may be in the presence and/or ratio of Ca and Mg. Usually people think if there is GH there must be Ca. Wrong. There may not be any Ca or any Mg and still get nice dGH readings.

Magnesium = GH - Calcium

Mg ppm = ((17.86 x dGH) - (2.5 x Ca ppm)) /4.1

*Example at 1 dGH:*

Ca : Mg [ppm]

7.0 : 0.0
6.0 : 0.7
5.0 : 1.3
4.0 : 1.9
3.0 : 2.5
2.0 : 3.1
1.0 : 3.7
0.0 : 4.4










Edward


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## plantbrain (Jan 23, 2004)

Generally folks with decent GH's have enough Mg and Ca(eg from Tap or reconsitiuted RO).

Sometimes there might be not enough Mg, but seldom Ca.

It's rare but possible and easily addressed with CaCl2 and MgSO4.
But few folks meausre Mg/Ca individually. 
I just suggest adding GH(both of these) or SeaChem Eq.

That takes care of things simply.
But you can try to induce Mg or Ca deficiency to see the effects if you want. 

Regards, 
Tom Barr


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## EDGE (Feb 28, 2004)

Just a quick follow up. Tap water in Lower mainland, BC has 0 Ca in it.


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## cS (Jan 27, 2004)

Edward said:


> Usually people think if there is GH there must be Ca. Wrong. There may not be any Ca or any Mg and still get nice dGH readings.


This is one the many reasons why people should contact their water company and request for a COMPREHENSIVE water report. It will detail the exact concentrations of Ca and Mg, among a host of other variables. The report is free.

I wish more people would participate in IUnknown's post so the "lazy" among us would have even less incentive to lift a finger. :|


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## MantisX (Sep 2, 2004)

What if you have well water?


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## EDGE (Feb 28, 2004)

Hello MantisX. Ca to Mg ratio in 1 gH should remain the same. The only difference between well water and tap water is the amount of solids is in the water.

It is best to grab a Ca, gH, kH, PO4, NO3 test kit to determine what is in the well water. Build your fertilizing regime around it.


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