Is there a diy PO4 reference solution?

[Miller535]

Is there a DIY reference solution for PO4? I would like to be able to make one and check it against my hanna checker and reagent.

 

[Miller535]

Perhaps @Randy Holmes-Farley already has a diy recipe for one.

 

[nereefpat]

We can help you do the math. What product are you using for phosphate?

You will need a scale, and you will have to make a big batch and do large dilutions to get to hanna checker levels.

 

[Miller535]

We can help you do the math. What product are you using for phosphate?

You will need a scale, and you will have to make a big batch and do large dilutions to get to hanna checker levels.

I have a few bottles of Neophos laying around. And I do have a gram scale that I bought on Amazon a while back.

 

[Randy Holmes-Farley Verified Community Expert]

Here's a commercial one:

Phosphate Standard Solution, 1 mg/L as PO4 (NIST), 500 mL

Phosphate Standard Solution, 1 mg/L as PO4 (NIST), 500 mL

www.hach.com

I would not use a hobby company dosing solution to make a standard.

If the goal is to evaluate a test kit, I think it will be useful to be in seawater.

 

[Miller535]

Here's a commercial one:

Phosphate Standard Solution, 1 mg/L as PO4 (NIST), 500 mL

Phosphate Standard Solution, 1 mg/L as PO4 (NIST), 500 mL

www.hach.com

I would not use a hobby company dosing solution to make a standard.

If the goal is to evaluate a test kit, I think it will be useful to be in seawater.

Yeah, you are probably right. Thanks Randy

 

[nereefpat]

I agree about not using a dosing solution.

Something like trisodium phosphate would be best. It is about 58% phosphate by weight, so adjust for that.

If the goal is to evaluate a test kit, I think it will be useful to be in seawater.

@Randy Holmes-Farley , do you expect some kind of interference?

 

[Randy Holmes-Farley Verified Community Expert]

I agree about not using a dosing solution.

Something like trisodium phosphate would be best. It is about 58% phosphate by weight, so adjust for that.




@Randy Holmes-Farley , do you expect some kind of interference?

Well, I'm not sure, but acidification is an important step in a typical phosphate test kit, and that will happen differently in freshwater than salt.

 

[SMSREEF]

Here's a commercial one:

Phosphate Standard Solution, 1 mg/L as PO4 (NIST), 500 mL

Phosphate Standard Solution, 1 mg/L as PO4 (NIST), 500 mL

www.hach.com

I would not use a hobby company dosing solution to make a standard.

If the goal is to evaluate a test kit, I think it will be useful to be in seawater.

How would one make a saltwater solution to test?
Would you just add your reef salt to this solution to make it 35ppt?

 

[Randy Holmes-Farley Verified Community Expert]

How would one make a saltwater solution to test?
Would you just add your reef salt to this solution to make it 35ppt?

I'd spike that standard (or a DIY) into new salt water that showed little to no phosphate. Since it is 1 ppm, 10% of it and 90% tank water would give a 0.1 ppm standard.

 

[SMSREEF]

I'd spike that standard (or a DIY) into new salt water that showed little to no phosphate. Since it is 1 ppm, 10% of it and 90% tank water would give a 0.1 ppm standard.

Fantastic. Thank you!

 

[Miller535]

I am looking for a place that sells it without high shipping. HACH shipping is $18, that's not much less then the solution itself.

 

[nereefpat]

I am looking for a place that sells it without high shipping. HACH shipping is $18, that's not much less then the solution itself.

14 bucks. Free shipping.
https://www.etsy.com/listing/780484...MIpM3iprHk7AIVkxatBh31igEaEAQYASABEgKii_D_BwE

That's the one I have.