[hidesertdude]

Hello,
I am new to the board and I have a question about mixing dry powdered fertilizer into water.
It is my understanding that when chemicals like calcium nitrate are mixed with water they slowly off gas nitrogen, resulting in a lower N ratio of the N-P-K of a fertilizer.
I would like to know how I can stabilize the calcium nitrate in water so it won't off gas, or at the very least will only off gas a small amount, this way I can make up stock solutions for hydroponics and they can be shelf stable for longer periods of time.

Thank you in advance for everyone's input. I really appreciate it.
Thanks, Ken

[Arkcon]

Hello,
I am new to the board and I have a question about mixing dry powdered fertilizer into water.

This is a frequent question on this forum, we're always glad to help.  You're working with hydroponics, which is always interesting for its peculiar problems, and for the simplicity of working with a soil-less system, because that removes some variables.

It is my understanding that when chemicals like calcium nitrate are mixed with water they slowly off gas nitrogen, resulting in a lower N ratio of the N-P-K of a fertilizer.

No.  That's false.  At least as you've written it here.  You may want to qualify the statement more, to talk more about what you really mean.  But if you have calcium nitrite, or potassium sulfate, or urea as other examples, and you make a stock solution, it will stay the concentration you made it, indefinitely.  I mean that as its defined -- forever, but without a defined point at which it loses potency.  You have to add qualifiers that are sourced for us to help you with all possible problems.

I would like to know how I can stabilize the calcium nitrate in water so it won't off gas, or at the very least will only off gas a small amount, this way I can make up stock solutions for hydroponics and they can be shelf stable for longer periods of time.

Thank you in advance for everyone's input. I really appreciate it.
Thanks, Ken

We're glad to help, once we know what we're really dealing with.

[hidesertdude]

Hello Arkcon,

This is a frequent question on this forum, we're always glad to help.  You're working with hydroponics, which is always interesting for its peculiar problems, and for the simplicity of working with a soil-less system, because that removes some variables.

Hydroponics is interesting. I use modular Kratky and modular Dutch bucket systems, so for the most part they are “plug and play.”
I can break the system down in portions when harvesting and not effect other portions, which is very convenient.
Hydroponics is nice but lacks the “feel” of a garden, it is more sterile which is fine with me.
As you said it cuts down on variables, making diagnosing issues a lot easier.

No.  That's false.  At least as you've written it here.  You may want to qualify the statement more, to talk more about what you really mean.  But if you have calcium nitrite, or potassium sulfate, or urea as other examples, and you make a stock solution, it will stay the concentration you made it, indefinitely.  I mean that as its defined -- forever, but without a defined point at which it loses potency.  You have to add qualifiers that are sourced for us to help you with all possible problems.

Ok, let me explain a bit better.
The fertilizer is a three part formula, the base fertilizer, calcium nitrate, and magnesium sulfate.
I have spoken to my fertilizer supplier, they have suggested to not leave a stock solution on the shelf for more than a few months, but they didn’t explain why.
The variables here could be many things, from the fertilizer solution growing algae from ambient light to the filler they are using going off and putrefying (42% of the fertilizer is filler, as is the case with most powdered fertilizers). I suspect the filler to be a form of cellulose.
I have mixed stock solutions before and left them for periods of 2 months and upon opening there is this distinct ammonia-like, chlorine smell (the smell is difficult to describe, I have nothing definite to compare it to) leading me to believe that the fertilizer is off gassing something.
Also I have run tests where I have “pre-mixed” the dry components, which have ended in failure. The fertilizer first turns to slush, then re-crystallizes into this lump. Also when mixing pre-mixed fertilizer into a stock solution, there is always sediment in the mixing container, which looks to be calcium on visual inspection.
When opening the containers of the pre-mixed fertilizer tests there was a very strong smell of this same ammonia-chlorine smell.
I did the test a few times to make sure the same results would occur and have not repeated it since.

Also, sometimes in the summer when I open the container I keep the dry calcium nitrate prills in (gamma seal on 5 gallon bucket), there is this same ammonia-chlorine smell, which by deduction leads me to believe the scent I am smelling in both the stock solution and the pre-mix are from the nitrogen.
The smell must mean something is off gassing, so I assumed it

Also I remember reading this somewhere, but I don’t remember where. I know that is very helpful!!!

My goal is to be able to mix something around a gallon or so of a “concentrated” stock solution that I can draw from over time.
The fertilizer I am using is a commercial fertilizer and it really isn’t suited to mixing in small batches.

Thank you again for all of your help, Ken

[hidesertdude]

Hello all,
To update, I wrote the fertilizer company and they suggested that I not mix the calcium nitrate into a “stock solution” until I am just about to use it because in a very short time the calcium will fall out of solution, there was not mention about how long this would take, just the vague term “short” was used.

I was also told this time around that a stock solution (base fertilizer and magnesium sulfate) shouldn’t be allowed to sit on the shelf for more than a “few” weeks, but I wasn’t given a reason why.


I have asked for clarification about what will happen to a stock solution (base fertilizer and magnesium sulfate) that is allowed to sit for a “few” weeks, because in reality I regularly make up stock solutions (which include the calcium) that sit for over a month and not only does the calcium not fall out of solution but there doesn’t seem to be any difference in fertilizer strength then fresh fertilizer.

I also asked if mixing the calcium nitrate with water and sitting it on a shelf causes the calcium to fall out of solution, then what are the companies that sell calcium and magnesium liquid products using because those are shelf stable….

So I will update again when I hear back from the company.

[Arkcon]

Hi there, hidesertdude:, I'm sorry we're not being more help to you, but you casually mix jargon, apply incorrect terms, and you're looking for an all encompassing answer, with random sketches of information. 

I really doubt I can solve your problem.  I just hope I can communicate to you why the solution to your problem, that you want, won't be achievable.

It is my understanding that when chemicals like calcium nitrate are mixed with water they slowly off gas nitrogen, resulting in a lower N ratio of the N-P-K of a fertilizer.

Nope.

The variables here could be many things, from the fertilizer solution growing algae from ambient light to the filler they are using going off and putrefying (42% of the fertilizer is filler, as is the case with most powdered fertilizers). I suspect the filler to be a form of cellulose.

Now those things are real, and they can affect your mixtures.  You waited a while to tell us about  them.

You concentrates aren't going to stay the same in long storage.  You mixtures will react with each other.  If you want to know about pure chemicals, when you only have commercial mixtures with fillers, I have to wonder why you ask at all.

To update, I wrote the fertilizer company and they suggested that I not mix the calcium nitrate into a “stock solution” until I am just about to use it because in a very short time the calcium will fall out of solution, there was not mention about how long this would take, just the vague term “short” was used.

Calcium nitrate is a very soluble salt.  Magnesium sulfate (Epsom salts) is very soluble too, I often add it to my soluble fertilizer for my garden.  Calcium sulfate, gypsum, is a common mineral, a rock.  You can't mix calcium nitrate and magnesium sulfate.  You will, in fact, "lose" calcium.  See, as the science of chemistry goes, we can't "lose" an element.  It just becomes insoluble, and no good for hydroponics, it would eventually be useful to plants in soil.

You'll probably get better results focusing on hydroponics forums, and sticking to the recipes they work with.

[hidesertdude]

Hello Arkcon,
I am not a chemist, I am a gardener trying to figure out a chemistry problem, so I apologize if my nomenclature isn't correct.
I believe we have gotten off topic.
All I really want to know is how to stabilize a saturated mixture of calcium nitrate and water.
The base fertilizer I am not worried about, I regularly mix this and leave it on the shelf for over a month with no issues. This is not the topic.

The topic is that I would like to know how I can keep a solution of calcium nitrate (or calcium nitrate and magnesium sulfate) stable in water so it doesn't lose calcium, nitrogen, and/or magnesium, and sulfur). This way I can mix saturated solutions of both fertilizers in separate containers and leave them side by side on a shelf to be combined prior to using in my hydroponic reservoirs.

As far as going to a hydroponic forum, I am not going to find my answer there... People will just tell me to buy some overpriced off the shelf product.
I know this can be done, there are products on the market, like Botanicare's Cal-Mag which the label says is just Calcium Nitrate and Magnesium Sulfate...

The Botanicare product is expensive and mixing my own Cal-Mag solution is much more cost effective, so I thought this would be a better route to go.

I appreciate any help anyone can offer, Thank you!

[Arkcon]

When I was playing with hydroponics, I mad a saturated solution of potassium chloride, because that was all I could get.  With a saturated solution, I could be be sure of making a nutrient solution at the level I wanted.  It was a disaster -- the strongest solution possible soon grew water mold.  A more dilute solution, of any nutrient, especially of an important nutrient like calcium nitrate, will be even more likely to spoil.  A concentrated solution might survive, unmixed, but the phenomena you describe, dropping out in storage unmixed, or evaporating off when a sealed container are opened, isn't based on chemistry -- its either spoilage, or mixing with another chemical.

[Borek]

With high Ca²⁺ concentration there is always a risk of CaCO₃ precipitation, CO₂ is quite capable of penetrating rubber seals, so even keeping the jar closed can be not enough.

[hidesertdude]

So then how do companies like Botanicare produce a "concentrated" Calcium (nitrate)-Magnesium (sulfate) product that is shelf stable?
I am not looking to keep this stuff on the shelf for years, just perhaps 3 months at most.


Botanicare Cal-Mag
https://www.botanicare.com/supplements/

SDS:
https://content.botanicare.com/wp-content/uploads/2017/05/Cal-Mag_Botanicare_SDSUSV4.7English.pdf



https://content.botanicare.com/wp-content/uploads/2017/05/BC_SUPPLEMENTS_0009_CALMAG.png


Thank you again for any and all help

[Arkcon]

Botanicare Cal-Mag Plus (2-0-0) Ingredients: Calcium nitrate, magnesium nitrate, iron EDTA.

A 2% solution of highly solute salts of calcium and magnesium.  No reaction can take place between them, since they're the same.  The company likely uses sterile water, and sterile filling.  The solution should keep, unopened,for a long time.  Might last a little while, if opened but sealed soon, but it could also spoil.

You've made a number of posts, that don't match this formula:  your slush was likely a very concentrated solution and Botanicare is a very weak one, Botanicare Cal-Mag Plus doesn't mention fillers, and I told you you'd get a reaction with calcium nitrate and magnesium sulfate, and you can see Botanicare uses the nitrate salt of both chemicals.

[Kristi]

I am not a chemist, but I do have a few years experience in growing.  I also use Botanicare Cal-Mag in addition to my Fox Farm fertilizers, because my nuts never seem to provide enough no matter how much I use. Some of my seedlings have even showed signs of deficiencies, because of the coco coir pellets. Anyway, I refuse to let my nutrients get old or warm so nothing much can be lost to time or temp problems for me. I lost enough money on my plants to make some people cry, because I used what I now believe were old and/or mishandled nutrients.

Anyway!!  I hate to be captain obvious, but have you tried refrigerating or freezing your nutrients? Because of my new found fears, I planned on storing mine in an old fridge or freezer this summer.