Which phosphate to dose?

[BantyRooster97]

I've been reading and searching, which phosphate are people using to dose?

Disodium Phosphate (Is the the same as sodium hydrogen phosphate)
Trisodium Phosphate

I've found both in food grade, not sure which to buy.

(After this I'll determine what mixing ratio to add)

thx!

 

[Randy Holmes-Farley Verified Community Expert]

Either is perfectly fine.

 

[BantyRooster97]

@Randy Holmes-Farley Is this the same thing?

Disodium Phosphate & sodium hydrogen phosphate

I found a listing for disodium phosphate which would be Na2PO4 and it says it is actually Na2HPO4.

Is this ok?

 

[BantyRooster97]

I've discovered trisodium phosphate is quite a bit more expensive than disodium phosphate

 

[Randy Holmes-Farley Verified Community Expert]

@Randy Holmes-Farley Is this the same thing?

Disodium Phosphate & sodium hydrogen phosphate

I found a listing for disodium phosphate which would be Na2PO4 and it says it is actually Na2HPO4.

Is this ok?

Those words mean the same thing.

There must always be 3 positive charges of something to go along with the phosphate, 3 Na+, 2 Na+ and one H+, 1 Na+ and 2 H+, or three H+. There's no such thing as Na2PO4.

 

[BantyRooster97]

Thanks as always @Randy Holmes-Farley !!

 

[Randy Holmes-Farley Verified Community Expert]

Thanks as always @Randy Holmes-Farley !!

You're welcome.

Happy Reefing

 

[Reefahholic]

So which did you end up buying and how is the dosing going?!

 

[Reefahholic]

Randy, what would you prefer to dose if your PO4 was zero.

Is there a particular product that is easier to mix up. I’d like to get a good “food grade” product that is good quality and mixes up well.

Most importantly...I want the best product that people seem to have the most success with and minimal issues.

 

[TMC1313]

This is the one I use. I weigh out 1.06 grams into 100 mls of RO/Di water. From this solution I add 1 ml to my 65 gallon tank which gives me a concentration of .03 ppm phosphate. You can use any plant calculator to calculate your dose for you, if you're reluctant to do the math yourself.

 

[Reefahholic]

This is the one I use. I weigh out 1.06 grams into 100 mls of RO/Di water. From this solution I add 1 ml to my 65 gallon tank which gives me a concentration of .03 ppm phosphate. You can use any plant calculator to calculate your dose for you, if you're reluctant to do the math yourself.

Looks good! Is this food grade?

Does anybody know what Randy’s first pick would be?

 

[TMC1313]

That one is not food grade, but for manufacturing and lab use.

 

[Reefahholic]

That one is not food grade, but for manufacturing and lab use.

Would that be better?

 

[TMC1313]

I guess, technically it's better, but I dont think food grade would have enough impurities to harm anything. I guess it would depend on the source.

 

[Reefahholic]

So nobody knows what brand that Randy is using or recommends?

 

[Randy Holmes-Farley Verified Community Expert]

Chemicals that say ACS Reagent on them (this one does) are typically a very good pick. They have stringent purity criteria set by the American Chemical Society.

The things that one is worried about in chemicals varies between food grade (is it OK to eat) and ACS reagent (is it sufficiently pure to do many sorts of chemical reactions without any interference).

For example, Sodium chloride ACS reagent has a limitation on potassium levels (K: ≤0.005%), I think.
Food grade NaCl doesn't.

Any food grade or ACS reagent grade product (or USP, BP, and some other grades too) are OK for things you know you want to dose.

 

[Randy Holmes-Farley Verified Community Expert]

FWIW, the more of something you add, the more important purity is.

If you add enough magnesium to boost a tank 100 ppm, purity is important because you are adding so much.

If you are adding enough iron to boost levels by 0.0001 ppm, it almost doesn't matter as long as it is "mostly" iron.