Salifert potassium test

[elysics]

So my salifert potassium test turned out very low on my tank (330), so I carefully added 30 ppm over 2 days and tested again, still 330. So I tested it on a reference solution and it actually showed high by about 50 ppm.

But the reference is old and almost empty,while the test is good until 2023 and only been bought a few months ago.

Does anyone know whether I can make a quasi reference by putting some potassium additive into rodi? Or will the test only work properly in saltwater?

Im asking because I have newer references for the other tests, just without a value for potassium on them and I am not keen on buying another bottle just for this test

 

[SPR1968]

I can’t answer the specific question but I can bump the thread for you to see if anyone can help out

 

[Randy Holmes-Farley Verified Community Expert]

So my salifert potassium test turned out very low on my tank (330), so I carefully added 30 ppm over 2 days and tested again, still 330. So I tested it on a reference solution and it actually showed high by about 50 ppm.

But the reference is old and almost empty,while the test is good until 2023 and only been bought a few months ago.

Does anyone know whether I can make a quasi reference by putting some potassium additive into rodi? Or will the test only work properly in saltwater?

Im asking because I have newer references for the other tests, just without a value for potassium on them and I am not keen on buying another bottle just for this test

No, you cannot use fresh water.

I'd use a new batch of 35 ppt salt water from a decent company as a rough standard. Most are pretty close.