Phosphate Reference?

[Shoestring Reefer]

Hi, Randy.

Our club has a LaMotte phosphate test, which was measured zero phosphates in a tank that is suspected of having a phosphate problem. We understand that it only measures orthophosphates, and phosphates may be taken up by algae so fast that it would be undetectable, anyways.

But, for the sake of making sure, do you know of how we can make (or where we can buy) a phosphate reference solution. My first guess was hand soap because I've heard it contains (or, used to) phosphate. Would that work?

Thanks in advance,

[Randy Holmes-Farley]

No, I don't think that would be a good way.

But if any of you have pH 7 calibration buffer, it is often 0.05 M phosphate (4.75 g/L or 4,750 ppm phosphate). It likely will say on it if that is what it is.

To make a standard:

1. Take 10 mL of this fluid and add to 1 gallon of water (= 12.5 ppm)

2. Take 50 mL of this 12.5 ppm fluid and add to 1 gallon of water (= 0.165 ppm)

[Shoestring Reefer]

Thanks, Randy. :)

[Randy Holmes-Farley]

You're welcome.

Let us know what you find. :)