Different test kits giving wildly different results?

[jonnythan]

This morning I used the API liquid nitrate test kit and the API nitrite/nitrate test strips on the same sample of water.

The liquid test kit gave me, to the best of my reckoning, about 10 ppm nitrate.

The strips gave me 40 ppm.

Is this... typical?

[jsoong]

Stripes are notorious for being inaccurate .... The API kit is quite good. To get a really accurate test (not really need for the typical hobbyist), you actually need to do the test with reference solutions.