[CrushnYuba]

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?

[CrushnYuba]

It's there really no one for this one? Magnesium oxide?

[Douglas.Curtis]

Why not epsom, are you maxxed on sulfur already? The nitrates in CalMag are why I don't use it.

[Avenger]

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]

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.

[pumpkinpie eyes]

try magnisal.

[Absolem]

Hey CrushnYuba

Avenger is top notch on fertilizer salts.

Check out this site. It contains all kinds of dry salts and the owner is super helpful.

https://customhydronutrients.com/

[CrushnYuba]

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]

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]

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+



and here is what Botanicare guarantees on the label.




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.