Bad Red Sea Nitrate and phosphate tests?

[sinful]

I bought a Red Sea kit over a year ago to test both nitrates and phosphates. From day 1 I have never tested any level of either one of them. I had a pretty bad algae problem back then and somewhat passed it off as the algae eating up both. Now, pretty much algae free it still test nothing for either. I'm starting to think the test kit has been bad since day one. Anyone heard or experienced Red Sea test kits being unreliable?

 

[CREATIVE AQ TMP]

Try adding a tiny bit of fertilizer to a test sample.