# Comparisons between Agricultural grade and Reagent ACS grade chemicals



## Maven (Jun 5, 2005)

(I posted this on plantedtank.net. I know the doctor posted on these boards (somewhere) as well so I thought I'd post it here also as some of you might be interested in this.)

Recently a doctor who takes care of his own large planted tank in his office made a post asking about the grade of the ferts Greg Watson sells. Greg Watson posted and said he buys agricultural grade chemicals in bulk. The doctor said he was uncomfortable with the fact that the impurities in the agricultural grades are unknown, as are their levels. Probably fine for agriculture, but he had rare fish and plants and wanted a better grade.

Most everyone attacked him, saying he was bashing Greg Watson and that he was an idiot for even thinking this mattered. The conversation wasn't even allowed to continue and the thread was locked.

I think it's a sad state of our hobby when new ideas get attacked without hesitation. I think it's a sad state of our hobby when certain people's words get taken as gospel without even an ounce of skepticism or questioning. Some of these certain people are even downright rude in character (I think you know who I mean).

I for one wanted to try ACS (American Chemical Society) grade chemicals for myself just to compare the difference in the agricultural chemicals I already have on hand from gregwatson.com.

It was suggested that the "end customer" can't order ACS grade chemicals as they are regulated by Homeland Security and the DEA. I found out that this isn't true. Many large lab suppliers won't sell chemicals to the end customer, but there are those who do and they aren't breaking any laws. I found one and ordered some reagent ACS Grade K2SO4, CaCl2*2H2O, and MgSO4*7H2O.

Here are some of the differences I noted:


With the Greg Watson chemicals, the formulas that were discussed and posted on the boards never quite yielded the expected results. For example, Hypancistrus, KevinC, and some other people got into computing dosages based on atomic weights. I think it was Hypancistrus who concluded that 79.39 milligrams of CaCl2*2H2O and 33.27 milligrams of MgSO4*7H2O will raise GH in 1 gallon of water by 1 dGH while maintaining a 4:1 ca:mg ratio. When actually doing this, my test results never quite matched this. For example, when dosing my tank at a water change (I use RO/DI water), I would compute dosages for raising GH. I target 6 dGH. But when I test after adding, I found that sometimes I would need to add 80%, sometimes 60%, or sometimes more, like 120% or 140%, to obtain my targeted dGH.

With the ACS chemicals, I found that the dGH increase EXACTLY matched the computations. I calculate and measure for 6 dGH, and the test results return 6 dGH. So far it's been consistent with 3 water changes.

This does lead me to question the purity of agricultural CaCl2 and MgSO4.

One thing I immediately noticed is that I didn't even have to stir to get the ACS chemicals to dissolve. I bought a stirrer after reading about them on the boards. When I measured the CaCl2 for example, poured in some water, and brought it to the stirrer, I found that I could see no solid pieces in the container. Just pouring in water was enough to get it to dissolve completely. I am not sure if this means anything significant, it is just a difference I am pointing out.

Finally, a picture comparison. This is K2SO4. These pictures were resized and sharpened a bit, but the color is unretouched. All pics were taken under the same lighting in the same position.

Greg Watson agricultural grade K2SO4:



















Reagent ACS grade K2SO4:



















Greg Watson agricultural grade K2SO4 - 1 teaspoon in 200 mL RO/DI water, on stirrer for 10 minutes:



















(The stir bar in the bottom is magnetic. The black specs on the stir bar must be a type of magnetized metal. The other stuff on the bottom is unknown matter which doesn't dissolve.)

Reagent ACS grade K2SO4 - 1 teaspoon in 200 mL RO/DI water, on stirrer for 10 minutes:


















I would like to emphasize that I am NOT "bashing" Greg Watson. I have never talked to him but from what I understand, he is a hobbyist like the rest of us and he's very nice. He says right on his site "these are for agriculture," he's not misrepresenting what he is selling in any way. The only thing he's doing that I think will eventually get him into trouble is he's shipping Potassium Nitrate via the US mail, which is a BIG no-no. He may just not realize the folly in doing this if he gets caught. He needs to switch to a carrier like UPS for this and he has to designate the package as a hazardous material (oxidizer). It's not me, that's just the rules. I don't like them either!

For me personally, I don't view my hobby as "growing weeds." I go nuts over the rare stuff and I don't mind paying extra to get it. That's part of the fun for me. This goes for plants and fish. One argument is "the unknown impurities are just trace elements so what's the problem." The doctor said it best, it's that the impurities are unknown and so are their levels. From what I have discovered above, I believe the levels of impurities in these agricultural chemicals is not as insignificant as believed. With reagent ACS chemicals, I can control the trace elements because I can remineralize my water with highly pure salts, then add a trace mix (I use Flourish) where the "impurities" and their levels ARE known and have been "tweaked" for planted aquariums. So, I have decided I am most comfortable with these reagent ACS chemicals.

I doubt the Doctor will visit the boards again after the extreme negative response he received, but if by chance he is reading, I'd like to thank him.

If you do a little searching on the net, you can get Reagent ACS chemicals for lower prices. Yes, they are more expensive than Greg Watson. Many people think a product is evil if it is more expensive. But then again many people love Amano and his products are probably some of the most expensive in the industry. Again for me personally, I don't mind paying a bit more. I initially bought small quantities, but they can be found for $30 - $40 per 5 pounds (which as most of you know will last a LONG time).


----------



## John P. (Nov 24, 2004)

Thanks for taking the time to compare. I'll probably still go the cheaper, Greg route, unless there's any harm in doing so (which I doubt).

Please keep us posted on your results!


----------



## dennis (Mar 1, 2004)

Thank you for taking the time to post this. Honestly, at APC we do appreciate different opinions. Spend some time here and you will realize that. The thread was locked not because of its differing opinion but because it started out somewhat hostile. We do not tolerate flame wars on APC, there is enough division between peoples, groups and forums already in this hobby. We would have, and do respect the Doctoers opinion; however, even you must admit he started his post off on the completely wrong foot. As for those rude characters, we don't tolerate any of that here and the people I assume you are refering to have also been asked to play nicely. No one, regarless of their experience or "status" in the hobby is given special privelages here.

There is no need to start that mentality up again. We do appreciate your post and sincerly respect the amount of time you are taking ot research this. Hopefully you will continue update us on the results of your comparsion as I think many of us will find the information/data interesting.

Hopefully the doctor does return, hopefully you will continue to be a part of our community


----------



## Salt (Apr 5, 2005)

Does anyone know what that stuff in the K2SO4 might be? Kind of looks like sand... then again some of it is sticking to that stir bar so it must be metal! The water also looks kind of tinted.

Maven, the "Doctor" posted in the Greg Watson forum.


----------



## Maven (Jun 5, 2005)

That's the thing, Salt, the impurities and their levels are unknown.

I see Dr. Quinn's post now. He made a list of what some of the impurities can be, I'm not sure of his source for it though. My own guess is this is only partial.



> The impurities present in these chemicals can include acid-insoluble matter, alkali compounds, aluminum, ammonium, arsenic, barium, calcium, chloride, copper, fluoride, heavy metals, helium, insoluble matter, iodate, iron, lead, magnesium compounds, manganese, nitrate, nitrite, organic volatile impurities, phosphate, selenium, sodium, sulfate, and sulfur.


----------



## Salt (Apr 5, 2005)

I saw your post over on plantedtank as well, just to mention here for anyone wondering... you can get Reagent ACS grade chemicals from Clarksonlab.com, chemsavers.com, or ebay.


----------



## plantbrain (Jan 23, 2004)

Maven said:


> That's the thing, Salt, the impurities and their levels are unknown.
> 
> I see Dr. Quinn's post now. He made a list of what some of the impurities can be, I'm not sure of his source for it though. My own guess is this is only partial.


And trace amounts are bad for plants?



> The impurities present in these chemicals can include acid-insoluble matter, alkali compounds, aluminum, ammonium, arsenic, barium, calcium, chloride, copper, fluoride, heavy metals, helium, insoluble matter, iodate, iron, lead, magnesium compounds, manganese, nitrate, nitrite, organic volatile impurities, phosphate, selenium, sodium, sulfate, and sulfur.


14 of these are plant nutrients
The others cause little issue at low doses and plants are used for phyto remeditation for the remainder for environmental clean up.

I would think the trace amounts would be far worse for animal life.
Plants are far more resistent to these chemicals.

Salts like K2SO4, KNO3 etc are fairly pure as they have very high melting points.

Suggesting they have these without backing up how much or if it's significant in terms of toxicology to aquatic life is simply meaningless information that scares, rather than shows any significant impact on our tanks.

I've used the ag grade stuff for the food I eat(if it's good enough for us, it's good enough for my fish certainly), the tanks I grow and I've not found any issues I could possibly trace to these supposed issues that you and Dr Quinn have stated.

Simply try it and see, was there anything wrong with the ag grade to begin with? For a decade on 300 species of weeds folks have used these products with excellent health and growth. Now why should I switch?

Common sense can really go a long way and save folks a lot of $.
I don't need science to see common sense issues.
I already know there no issue with the ag grade products.
So do many other folks.

Regards, 
Tom Barr

www.BarrReport.com


----------



## Bert H (Mar 2, 2004)

From Tom's post:


> 14 of these are plant nutrients


That pretty much closes the case, in my book. And as was also pointed out, this is the stuff that grows the food that we eat :!:

Folks have to keep in mind that the purity level required in scientific studies has to be much higher. This is where ACS materials come in. Heck, why not feed our plants molecular biology grade (99.99% pure) chemicals?! Now if some of you are doing tissue culture studies on some plants or trying to come up with the latest dwarf variety of something, perhaps you might need purer chemicals. For the rest of us, our past experiences should tell us what does and doesn't work.


----------



## Salt (Apr 5, 2005)

plantbrain said:


> I've used the ag grade stuff for the food I eat(if it's good enough for us, it's good enough for my fish certainly


You wouldn't mix animal manure in with the substrate in your planted tank with fish would you? [smilie=k:

I don't get the big controversy this is causing over at plantedtank. So there's a higher quality product available for people who want it. Just like there's $300 CD Players and $3000 CD Players that do the same thing. What's the problem? :|


----------



## TeutonJon78 (Nov 10, 2004)

The difference between using the Ag grades chemicals to grow your foot is that the ground is taking the excess chemicals. The plants are only using the "good" part of the fertilizer. Now, contaminating the ground is another story all together.

But in an aquarium, any impuries are put directly into the water column where they will continue to be with (and move towards higher concentrations which could at "some" point -- which may be 100 years for all I know-- contaminate the substrate) our precious fish and plants.

If people are comfortable with using Ag grade stuff with unknown impurities (with has no relation to Greg W. or his product offerings), then use Ag stuff. If you want to know exactly what you're getting, spend a little extra and get the pure stuff.


----------



## TWood (Dec 9, 2004)

This hobby seems to go through cycles where new reasons for FUD (Fear, Uncertainty, Doubt) gain traction, fade, and then hang around for years. Sonic needle valves and other CO2 myths, Kelvin and lumens, PO4/algae, and a host of other issues have gotten in the way of success for many people. It would be a shame if this so-called 'impurity' issue causes much FUD [smilie=p: when the ag-grade fertilizers already have a history of success. 

TW


----------



## dennis (Mar 1, 2004)

I agree with TWood and I must say there is really no need to argue this further. Any postings stating *facts* concerning either side of this issue are welcome. It would be intersting, and might even prove useful one day, to know the actual purities or other scientific data regarding the various grades; however, any *speculation* or information not pertaining the the chemicels themselves is a mute point. *Case closed*.


----------



## Salt (Apr 5, 2005)

I may (if it's not too expensive) send samples of my GW compounds in to a lab for analysis, if only to satisfy my own curiosity since this issue has been raised. One thing to remember is even if I do that, the "impurities" will vary from batch to batch. From what I understand, most of this stuff is mined, and the "agricultural grade" is usually just sieved. One person over at plantedtank speculated that the stuff you're seeing in the K2SO4 is due to rusty sieves. The "ACS" stuff usually goes through one or more purification processes.

I'm open to any suggestions as to where to find a lab to do the testing... preferably somewhere I can easily send the samples to via the mail. If it costs too much I won't be able to do it.


----------



## plantbrain (Jan 23, 2004)

Salt said:


> You wouldn't mix animal manure in with the substrate in your planted tank with fish would you? [smilie=k:
> 
> [/QUOTE]
> 
> ...


----------



## Salt (Apr 5, 2005)

What's "FUD" ?

_edit_ - Read post above... "fear, uncertainty, doubt"



> You can set up test to learn rather than run scared and waste the $.


I would hope my motivation is to learn... not sure what you are implying?

I do appreciate all your info!


----------



## plantbrain (Jan 23, 2004)

Salt said:


> I would hope my motivation is to learn... not sure what you are implying?
> 
> I do appreciate all your info!


Salt, the issue is what the *real question* actually is.
We can run off and waste time, $, resources etc chasing after something that does not address the application and the questions folks have..........spilling FUD everywhere in the process......that's why I pointed to using RO water, measuring the contents of fish food, air purifiers etc....
there is no end to FUD and marketing.........

The learning here is not to be a sucker.....

This is learning............learning beyond the constituent of what crap is in ag grade stuff, rather, does it make any significant difference in context of aquatic horticulture?

These are entirely different questions.
One will answer the real question, the other will merely answer whether there are a certain amount of X, Y or Z in the ag grade vs Research grade(or whatever grade you chose) chemicals.

Now what does the amount of X, Y and Z tell you after you went to all that trouble?

The learning I'm suggesting is critical thinking, and asking the proper questions to answer and see through all the FUD.

Ask a "good" question, not one that leads to a dozen gazillion other questions and ton more test that are even tougher to answer and lead you to NOWHERE without a lot of resources.

We are aquarist, we need to keep the test simple to answer the question.
There are much more clever ways to see through the issue and design a simple test to find out.

Folks said excess PO4 causes algae. Well, I added excess PO4, no algae, end of story.

It's;s easy to prove what something is not, it's more difficult to prove what something is.

Reflect back on your own common sense here. Was there any issue prior?
Have I ruled out poor maintenance, low CO2, enough NO3?

The history that ag grade chemicals have is long and folks have not been able to trace any issues to it.

This will help you solve future issues far better than this wasteful procedure.

Even if we found As, Ba, Cd etc in the ag chemicals, how much is toxic?
How much will cause issues for plants? fish? Shrimps?

I've done a lot of work with ferts, I've added far more than most folks ever would consider. I did kills some shrimp on purpose last week. I added 120 ppm of NO3 for 3 days. No algae, no fish death, but the shrimp were not happy at this insanely high level.

Similar patterns exist for PO4/Traces/GH/KH/K+.

Maybe is was some other contaminant? So don't add that much NO3

You can use the plants as the gauge as to whether the different grades do better, but you need controls and need to Maintain stable similar conditions for each test.

That's tough for hobbyist, but over time you Can get a feel, it's still a better solution that the proposal which really will not answer the real question, is it worth it for folks to pay 10-50X more for ferts.

Maven says yes, I say no.

I'm not suggesting anyone __not learn or experiment__, quite the opposite, I am suggesting more thought be put into the experiment and __ask__ how to design one that might answer the question without introducing more FUD.

Apparently many don't see this distinction, think I have some attitude or ivory tower BS. They run off testing without much purpose, making lots of work and added expense for themselves, not answering the real question.

Can I grow plants super without the other grades? The same thing can be said about RO water. Does RO, higher fert grades help plants?.

Learning what NOT to do is... as... if not more helpful. 
Should you set up a heater cable test also?
No.......

Regards, 
Tom Barr

www.BarrReport.com


----------



## Edward (May 25, 2004)

Hi

There is nothing wrong with small quantities of other elements in the agricultural grade fertilizing chemicals. 
Maven, if you have to add 60 – 140% more minerals to obtain the calculated dGH then there is something else wrong in the process. Not the impurities.
Maybe the CaCl2 is not really the CaCl2 we think it is. Personally I wouldn’t use products like ice melt and stump remover and so on. We can never be sure what’s in it. People often confuse these with agricultural chemicals.

I’ve been running aquariums without water change for years where Tetras are breeding and plants are growing. No toxicity.

The chemicals I use are agricultural grade bulk 50lb bags. 

One more issue worth mentioning is the Luxury uptake of plants. Plants take a variety of elements even though they don’t need them and they store them in their tissue. Especially toxic elements. Plants are also used to detoxify contaminated fields. 


Thank you
Edward


----------

