Orenda PR-10000 versus cheap Lanthanum Chloride salt crystal

[chem geek]

Yes, that is correct, but it's 10,000 ppb of phosphates in 10,000 gallons. That tells you how much lanthanum carbonate would be required (which is higher due to its higher molecular weight), but don't forget that products such as PhosFree are no where near 100% pure. Usually the instructions on the label say how much product is needed to remove a certain amount of phosphate.

[EDIT] See my later post below -- I neglected to account for the factor of two due to lanthanum carbonate having two lanthanum atoms. [END-EDIT]

 

[smackdab]

Thanks. Yes I understand one product would be different from the next and one would follow the instructions but this is coming from a math and scientific standpoint.

So 977 grams of Lanthanum Chloride would remove 10,000 ppb of phosphates in 10,000 gallons and
1824.5 grams of Lanthanum Carbonate would remove 10,000 ppb of phosphates in 10,000 gallons.

Is this right?

 

[chem geek]

I forgot that there are TWO lanthanum in lanthanum carbonate (La₂(CO₃)₃) compared to one in lanthanum chloride (LaCl₃) so the correct answer is 977 * ((457.838 / 2) / (245.26 / 1)) = 911.91 grams to remove 10,000 ppb of phosphates in 10,000 gallons.

That is, one should use the molecular weight per lanthanum atom in the calculation.

 

[smackdab]

Got ya. Thats way over my head how you come up with these formulas. Thanks.

 

[chem geek]

The molecular weight of phosphate, PO₄^3-, is 94.9714 g/mole. 10,000 gallons is 37854 liters so 10,000 ppb phosphate which is 10 ppm (mg/L) phosphate is 10*37854 = 378540 mg which is 378.54 grams of phosphate.

It takes (378.54 g phosphate) * (245.26 g/mole lanthanum chloride) / (94.9714 g/mole phosphate) = 977.57 g lanthanum chloride.

It takes (378.54 g phosphate) * (457.838 g/mole lanthanum carbonate) / (2 lanthanum per lanthanum carbonate) / (94.9714 g/mole phosphate) = 912.43 g lanthanum carbonate.

I did less rounding so the numbers aren't exactly as I wrote before.

 

[smackdab]

These formulas make more sense to me than the one in post 3. Thanks for rewording it. You did make one mistake. You put lanthanum chloride instead of lanthanum carbonate at the end of the third paragraph. I knew what you meant though.

 

[chem geek]

Fixed. Thanks for catching that.