Comparisons between Agricultural grade and Reagent ACS grade chemicals - Fertilizing - Aquatic Plant Central

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Old 06-05-2005, 07:38 AM   #1 (permalink)
 
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Default Comparisons between Agricultural grade and Reagent ACS grade chemicals

(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).
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Old 06-05-2005, 08:00 AM   #2 (permalink)
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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!
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Old 06-05-2005, 08:29 AM   #3 (permalink)
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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
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Old 06-05-2005, 10:18 AM   #4 (permalink)
 
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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.
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Old 06-05-2005, 11:02 AM   #5 (permalink)
 
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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.

Quote:
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.
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Old 06-05-2005, 12:28 PM   #6 (permalink)
 
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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.
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Old 06-15-2005, 09:17 PM   #7 (permalink)
 
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Quote:
Originally Posted by Maven
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?

Quote:
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
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Old 06-16-2005, 05:05 AM   #8 (permalink)
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From Tom's post:
Quote:
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.
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Old 06-16-2005, 09:13 AM   #9 (permalink)
 
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Quote:
Originally Posted by plantbrain
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?

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?
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Old 06-16-2005, 09:46 AM   #10 (permalink)
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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.
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