How Much Dry Ferrous Gluconate To Make 10,000 ppm Solution

[jeff5614]

I recently picked up some dry Ferrous Gluconate from Aquariumfertilizer.com to replace the Flourish Iron I've been using. The directions that came with the ferrous gluconate say to use 36.6 grams / 1 liter of water to make a 10,000 ppm solution. I was just over at their website and the directions there say to use 95 grams / 1 liter to make a 10,000 ppm solution. Any idea which is correct and how do you calculate the amount needed to make a 10,000 ppm solution?

Thanks!
Jeff

 

[Tug]

Aquariumfertilizer.com, can't live with um, can't live w/out um.

I found this,

36.3 grams per liter to make standard 10,000 ppm solution.

Hope it helps.

 

[Tom Barr]

I found this,

Hope it helps.

That's wrong.
95 grams is correct.


Regards,
Tom Barr

 

[jeff5614]

Thanks! I decided to email and ask. Their supplier had misfigured the ratio initially which is where the 36 gram amount came from.

 

[Tom Barr]

Thanks! I decided to email and ask. Their supplier had misfigured the ratio initially which is where the 36 gram amount came from.

That was my mistake and fault, not theirs.

Regards,
Tom Barr

 

[jeff5614]

That's no problem at all. They're still my go to place for ferts.

 

[Wet]

FWIW, using molar mass for Fe from C12H24FeO14 gives 12.46%, which would be ~ 80.3g in 1L for 10,000ppm Fe. I'm using these links that nfrank pointed me to off forums:

http://en.wikipedia.org/wiki/Iron(II)_gluconate
http://www.vgdusa.com/chelated_miner...on_lithium.htm
http://www.drugs.com/ppa/ferrous-salts.html

The calculator here does this, too: http://wet.biggiantnerds.com/fe_calc.pl But perhaps this is wrong.

If you can measure the weight of a levelled teaspoon a fw times, Jeff, it's appreciated. I would not trust the tsp weight my calculator provides (which I also worked out from AquariumFertilizer.com's site) without another real trial.

Happy to trade you an equal portion of EDDHA or DTPA so I can test the weight myself, too

 

[Tom Barr]

It is more like 11%, not 12.46, you left out 2 hydrations.

You can also compare it to 6.53% for Fe in CMS.
The same weight should yield about 6200 ppm solution.
If this is incorrect, then all the CMS calculators are also incorrect.

Regards,
Tom Barr

 

[Wet]

Chemistry is cool. Thanks, Tom. Reading.

 

[Tom Barr]

Well , you can use past estimations and % Fe as a reference to check things eg, CMS etc.........and then knowing what the % is for any Fe dry powder, should be able to get close.

You can also just think about adding 10,000mg/l of "Stuff". So then it's 10 grams of "Stuff" for 10,000ppm or mg/l. Take the 11 % factor and you end up with a little under 100 grams.

********
Not that any of this really matters, if you are off by 2-3-5x even, as long as you dose a fair amount ezxcess of traces, there's no limitation and few folks bother to test Fe in their tank's water anyhow.
Most dosing is done by eye and general estimations.
*********
If we want to get specific and know more, then it does, toxicity, max /min values etc.........but for most, it really doesn't matter that much.




Regards,
Tom Barr

 

[barbarossa4122]

Hi,

Any idea how many grams of dry Ferrous Gluconate from Aquariumfertilizer.com are in 1 tsp?

Edit: 3.72gr/tsp
http://www.aquaticplantcentral.com/forumapc/fertilizing/69694-mixing-my-own-micros.html