Randy's Elements to Dose

[Randy Holmes-Farley Verified Community Expert]

No, the math is off, but I’ll have to redo it tomorrow.

 

[Randy Holmes-Farley Verified Community Expert]

Thank you so much for all your help as always. The local chemical company has Iron (II) Sulphate Heptahydrate. That is Ferrous Sulphate, isnt it? Their web page says, minimum assay >98.1% (screenshot attached).
Is my math correct:

If i dissolve 1g in 1L, concentration is 981 gr/L, or 981 ug/ml.
Adding 1ml (981ug/ml) to 100L will boost iron by 9.81ug/L. Is that correct?

And lastly, probably is not a good idea to mix it with the cobalt chloride, but since the cobalt will be in a very small amount- do you think that should be ok? I will probably give it a try and carefully look for precipitation but wanted to check with you first in case there is something very basic that i am missing.

Thanks a lot.

Iron (II) sulfate heptahydrate is 20% iron by weight.


Dissolve 1 g in 1 L RO/DI, and the iron concentration is 200 mg/L, or 200 ug/mL.

Adding 1 mL (200 ug) to 100 L of aquarium water boosts cobalt by 2.0 ug/L.

 

[acro_lover]

No, the math is off, but I’ll have to redo it tomorrow.

Thanks a lot @Randy Holmes-Farley,

Iron (II) sulfate heptahydrate is 20% iron by weight.


Dissolve 1 g in 1 L RO/DI, and the iron concentration is 200 mg/L, or 200 ug/mL.

Adding 1 mL (200 ug) to 100 L of aquarium water boosts cobalt by 2.0 ug/L.

understood, thanks for correcting it. So when looking at the element specification, i should be looking at the molecular weight and use that to calculate the dose? Did i understand correctly?

 

[Randy Holmes-Farley Verified Community Expert]

Thanks a lot @Randy Holmes-Farley,

understood, thanks for correcting it. So when looking at the element specification, i should be looking at the molecular weight and use that to calculate the dose? Did i understand correctly?

Yes, for figuring out doses, one needs to know the percentage of the element (say, iron), in the overall material. In this case, that comes from the molecular weight of iron (55.8 g/mole) out of a total molecular weight of 278 g/mole.

note that if there is more than one of something in the material, you need to account for that. For example, chloride (mw = 35.5 g/mole) in calcium chloride, CaCl2 (mw = 111 g/mole) is 2 x 35.5/111 = 64% by weight chloride.

 

[acro_lover]

Yes, for figuring out doses, one needs to know the percentage of the element (say, iron), in the overall material. In this case, that comes from the molecular weight of iron (55.8 g/mole) out of a total molecular weight of 278 g/mole.

note that if there is more than one of something in the material, you need to account for that. For example, chloride (mw = 35.5 g/mole) in calcium chloride, CaCl2 (mw = 111 g/mole) is 2 x 35.5/111 = 64% by weight chloride.

Understood, thanks for the explanation @Randy Holmes-Farley and for all your help. As i previously mentioned I am missing the basics of chemistry but i am good in Math as I am electrical engineer. Just need a little bit of help and will start trilaling it now. I have two big sps systems and have starred a smaller third one now. The new one will run only on DIY trace elements and your two part. I will do my very best to keep the water perimeters as close as possible to the natural seawater, therefore will be adding my diy trace elements every morning ( similar to the Moonshiner's methos).
I was trying to find something for Vanadium in your archive, but failed. I have picked Vanadium (V) Oxide >98%
Do you think thats a good choice?

 

[Randy Holmes-Farley Verified Community Expert]

Understood, thanks for the explanation @Randy Holmes-Farley and for all your help. As i previously mentioned I am missing the basics of chemistry but i am good in Math as I am electrical engineer. Just need a little bit of help and will start trilaling it now. I have two big sps systems and have starred a smaller third one now. The new one will run only on DIY trace elements and your two part. I will do my very best to keep the water perimeters as close as possible to the natural seawater, therefore will be adding my diy trace elements every morning ( similar to the Moonshiner's methos).
I was trying to find something for Vanadium in your archive, but failed. I have picked Vanadium (V) Oxide >98%
Do you think thats a good choice?

Here's a copied recipe. Note that you likely need to add some sodium hydroxide (use food grade lye) to get it to dissolve:

If you have a decent scale, I'd dissolve 4 grams in a liter (saturation is about twice that).

Vanadium pentoxide is about 54% vanadium by weight, so that solution will be about 2,200 ppm (mg/L) or 2,200 ug/mL.

1 mL of this added to 100 gallons (378.5 L) will boost vanadium by 2,200 ug/mL * 1 mL / 378.5 L = 5.8 ug/L.

That's a bit high, so if you dilute the stock again (100 mL into 1 L total) then it is 1/10th as much, or 0.6 ug/L final concentration when dosed 1 mL to 100 gallons.



I looks like only a fraction of the 4 grams in 1 L of r/o water dissolved.

I'd try about 0.9 grams NaOH in that liter with 4 grams vanadium pentoxide and see what that does.

Success! I ended up adding 1.8 grams of sodium hydroxide. 0.9 grams didn’t dissolve it completely.

https://www.reef2reef.com/threads/vanadium-pentoxide-need-help-from-the-big-brains.409810/

 

[ReeferZ1227]

Excellent thread @Randy Holmes-Farley thanks again for another great contribution.

 

[Randy Holmes-Farley Verified Community Expert]

Thanks and Happy Reefing! :)

 

[RMS18]

Ok not bad, Im only dosing two you recommend NOT to dose. I'm a moonshiner, shh don't tell the ATF.

 

[Randy Holmes-Farley Verified Community Expert]

Ok not bad, Im only dosing two you recommend NOT to dose. I'm a moonshiner, shh don't tell the ATF.

lol

Can guess which those are: barium and rubidium.

 

[RMS18]

lol

Can guess which those are: barium and rubidium.

Ding ding ding!

 

[acro_lover]

I truly appreciate all the help and advice you’ve shared, @Randy Holmes-Farley . Your contributions make a significant difference in the reefing community, and we are all grateful for your support. Wishing you and all members Merry Christmas and Happy Reefkeeping!

 

[acro_lover]

Here's a copied recipe. Note that you likely need to add some sodium hydroxide (use food grade lye) to get it to dissolve:

If you have a decent scale, I'd dissolve 4 grams in a liter (saturation is about twice that).

Vanadium pentoxide is about 54% vanadium by weight, so that solution will be about 2,200 ppm (mg/L) or 2,200 ug/mL.

1 mL of this added to 100 gallons (378.5 L) will boost vanadium by 2,200 ug/mL * 1 mL / 378.5 L = 5.8 ug/L.

That's a bit high, so if you dilute the stock again (100 mL into 1 L total) then it is 1/10th as much, or 0.6 ug/L final concentration when dosed 1 mL to 100 gallons.



I looks like only a fraction of the 4 grams in 1 L of r/o water dissolved.

I'd try about 0.9 grams NaOH in that liter with 4 grams vanadium pentoxide and see what that does.

Success! I ended up adding 1.8 grams of sodium hydroxide. 0.9 grams didn’t dissolve it completely.

https://www.reef2reef.com/threads/vanadium-pentoxide-need-help-from-the-big-brains.409810/

Hi @Randy Holmes-Farley , can I use

Sodium Hydroxide Pellets 97.0 - 100.5% ACS​

is there any significant difference between sodium hydroxide on pellets and lye? Probably not, isnt it!?

 

[geologeek]

Hi @Randy Holmes-Farley , can I use

Sodium Hydroxide Pellets 97.0 - 100.5% ACS​

is there any significant difference between sodium hydroxide on pellets and lye? Probably not, isnt it!?

Perfectly fine to use, the only limiting factor will be the pellet size Vs being in powder form is your ability to measure out a small amount......be extremely careful and use appropriate PPE if you need to crush a pellet up.

 

[Randy Holmes-Farley Verified Community Expert]

As geologeek notes, ACS grade is a good purity for reefers. The grade requirement tests are typically are a little different than food grade, but not worse and both are good. The main test useful for us are the contaminating metals.

 

[acro_lover]

Thanks a lot for your help, I really appreciate it. Does anyone have a link for a decent scale, that can be calibrated to 1-5g. Most that i find on ebay or amazon are calibrated at 50-200gr. I guess the accuracy wont be good enough at 1-5g

 

[geologeek]

Thanks a lot for your help, I really appreciate it. Does anyone have a link for a decent scale, that can be calibrated to 1-5g. Most that i find on ebay or amazon are calibrated at 50-200gr. I guess the accuracy wont be good enough at 1-5g

I recently bought a 0.001g scale on AliExpress for £11 and it tallies at the 1g with my much more expensive 0.1g ohaus scale.......

The brand is DigiWeight if you fancy it.

 

[Randy Holmes-Farley Verified Community Expert]

I also recently bought a scale. They are surprisingly inexpensive now. I got up to 1 kg total weight and 0.01 gram precision for less than $20 and a weight set to check accuracy for less than $10. It was Bomata brand, but I know nothing about that brand compared to others.

 

[acro_lover]

I recently bought a 0.001g scale on AliExpress for £11 and it tallies at the 1g with my much more expensive 0.1g ohaus scale.......

The brand is DigiWeight if you fancy it.

do you still have the link?

 

[geologeek]

do you still have the link?

I don't I'm afraid, but just search for 0.001g precision scales and you will find plenty for under a tenner in the sales at the moment