Sodium Phosphate Dibasic, Anhydrous. OK to dose/how much?

[BigJohnny]

Hey Randy,

Is this product okay to mix in RO and dose into my reef tank to raise phosphate levels? There were several formulations available but this had the shortest molecular formula so I thought that equalled purest (not sure if that checks out haha).

Also, how would I determine how much to dose to raise my tank by a certain ppm (or ppb, I have the Hanna ULR phosphorus which reads ppb and I have to convert to ppm phosphate).

Thanks!

 

[Randy Holmes-Farley Verified Community Expert]

I can't see the actual purity, but it is likely fine.

Do you have a scale for measuring?

 

[BigJohnny]

I can't see the actual purity, but it is likely fine.

Do you have a scale for measuring?

I believe it is 100%, Reagent Grade (I think that means 100% pure)

Yes, I have two scales, one that measures up to 200g at .00 and one that measures up to 80g at .000.

 

[BigJohnny]

I have estimated 110g total water volume.

 

[Randy Holmes-Farley Verified Community Expert]

Reagent grade is good. In general, the percentage is not that useful in revealing the purity.

That material is 67% phosphate.

Adding 1 gram (1000 mg) to 110 gallons (416 L) water volume will boost phosphate by 1,000 mg x 0.67/416 L = 1.6 mg/L

Too much.

Dissolve 1 gram of the product in 1 L of RO/DI, and add 10 mL of this liquid to your tank and you will boost phosphate by 1.6/100 mg/L = 0.016 mg/L.

 

[BigJohnny]

Reagent grade is good. In general, the percentage is not that useful in revealing the purity.

That material is 67% phosphate.

Adding 1 gram (1000 mg) to 110 gallons (416 L) water volume will boost phosphate by 1,000 mg x 0.67/416 L = 1.6 mg/L

Too much.

Dissolve 1 gram of the product in 1 L of RO/DI, and add 10 mL of this liquid to your tank and you will boost phosphate by 1.6/100 mg/L = 0.016 mg/L.

You are THE man. Thanks!

 

[BigJohnny]

Mg/l phosphate is basically ppm phosphate right? So adding 10ml of the 1g/L solution will add .016 ppm phosphate? Just making sure

 

[Randy Holmes-Farley Verified Community Expert]

Mg/l phosphate is basically ppm phosphate right? So adding 10ml of the 1g/L solution will add .016 ppm phosph weighs more than 1 kgate? Just making sure

Very close, yes.

The reason for a difference is that 1 L of seawater weighs more than 1 kg.

ppm is exactly equivalent to mg/kg, not exactly mg/L

 

[BigJohnny]

Very close, yes.

The reason for a difference is that 1 L of seawater weighs more than 1 kg.

ppm is exactly equivalent to mg/kg, not exactly mg/L

Great thanks

 

[pygoplites77]

Reagent grade is good. In general, the percentage is not that useful in revealing the purity.

That material is 67% phosphate.

Adding 1 gram (1000 mg) to 110 gallons (416 L) water volume will boost phosphate by 1,000 mg x 0.67/416 L = 1.6 mg/L

Too much.

Dissolve 1 gram of the product in 1 L of RO/DI, and add 10 mL of this liquid to your tank and you will boost phosphate by 1.6/100 mg/L = 0.016 mg/L.

hello and sorry if I disturb you. in Italy I only managed to find the Sodium phosphate monobasic dihydrate but I can't understand the doses for a 1 liter solution and how much I should then dose in the aquarium. Could you help me? Thanks and sorry for my english

 

[PicassoDan]

pygoplites77, did you figure this out?

 

[dragon99]

@pygoplites77 This thread talks about the dosing of monosodium phosphate

Dosing monosodium phosphate

Can someone check my math here? I'd like to raise my phosphates by 0.01ppm using monosodium phosphate (NaH2PO4). I have approximately 55g (208L) of volume. NaH2PO4 = 119.98 g/mol, PO4 = ~95g/mol. ? mg/ 208L = 0.01ppm 208 * 0.01 = 2.08 mg Is this correct? If so, I might mix 1L of RODI with...

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