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Magnesium nitrate, oxide, calmag diy.

CrushnYuba

Well-known member
I know there have already been threads on this. I'm trying to make a diy calmag plus. I have calcium nitrate kicking around. I don't have magnesium nitrate and I'm having trouble finding it. Don't want to use epsom.
The only mag nitrate i can find has allot of magnesium oxide in it as well. Is this available to plants? Do i account for the mag oxide in my ratios?
 

Avenger

Well-known member
Veteran
Fertilizer labels in some European countries require the magnesium, calcium, sulfur ect to be listed on the fertilizer label in the oxide form. In the USA we do the same thing for phosphorus and potassium by listing them on the label as P2O5 and K2O, phosphorus pentoxide and potassium oxide. See page seven in this LINK.

So Magnesium nitrate doesnt really have 16% magnesium oxide and 9.6% magnesium, it is just two different ways regulators allow the content to be quantified.

A substance that has 16% MgO actually has 9.6% magnesium. Because Magnesium oxide is 60.31 percent magnesium by weight.

16 times 0.6031 = 9.6

Magnesium nitrate has 9.6% w/w water soluble magnesium content.
 

G.O. Joe

Well-known member
Veteran
50# bags of it are ridiculously cheap. But if you had nitric acid pH down you could just basify that with the carbonate, which precipitates from mixing solutions of the sulfate and baking soda.
 

CrushnYuba

Well-known member
Avenger: thank link is blocked for some reason. Thank you for explaining that.
And how does calcium nitrate, mag nitrate, and iron edta end up being 2 for n in all the commercial calmag formulas? Wouldn't it end up being much more then that? I do want a bit of extra N but not that much.
I'm trying to figure out the cheapest possible way to do calmag. Calmag is just so easy and I'd love a cheap way to do it. Dropping 500 gallons a day minimum drain to waste in a soiless mix can get pricy if i used calmag the way i wanted to.
 

growingcrazy

Well-known member
Why not come up with a solution to not run calmag? I don't see it as necessary.

What medium are you working with?
 

Avenger

Well-known member
Veteran
IC mag automagically adds an S to any http link. here is the address the link was supposed to take you to.
h t t p://eur-lex.europa.eu/legal-content/En/TXT/PDF/?uri=CELEX:02003R2003-20130607&rid=2

And how does calcium nitrate, mag nitrate, and iron edta end up being 2 for n in all the commercial calmag formulas? Wouldn't it end up being much more then that?

Yes, it is quite common for manufacturers of liquid hydro store fertilizers to be less than transparent on their labels. The label is a guaranteed minimum, and does not have to be accurate.

for example here is an analysis for botanicare calmag+

attachment.php


and here is what Botanicare guarantees on the label.

attachment.php



As you can see the nitrogen content is near three times what they guarantee. I guess the plus is all the free chloride they give you with out telling you so on the label.
 

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CrushnYuba

Well-known member
Growing crazy: i havent been using calmag. Just when i have it's so sweet it And forget it. It just makes everything so green overnight and i guess allot is because of the nitrate. My fertalizer is a little low in n for veg.

Avenger: that has been so helpful. What do you think that chloride comes from? Do you think there is an added calcium chloride or something?
 

G.O. Joe

Well-known member
Veteran
Calcium and magnesium acetates if acetate doesn't cause problems are soluble, if you don't want any more nitrate or sulfate.
 

Only Ornamental

Spiritually inspired agnostic mad scientist
Veteran
...
Yes, it is quite common for manufacturers of liquid hydro store fertilizers to be less than transparent on their labels. The label is a guaranteed minimum, and does not have to be accurate.

for example here is an analysis for botanicare calmag+
View Image

and here is what Botanicare guarantees on the label.
View Image

As you can see the nitrogen content is near three times what they guarantee. I guess the plus is all the free chloride they give you with out telling you so on the label.
WTF! That one contains (on a mol base) 5 times more chloride than nitrate! Are they even allowed to do that? The "Derived from" only lists nitrate and sure, chloride is a common contaminant in agricultural grade salts but c'mon 5 times more contaminant than product just ain't right!
 
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