Are test strips inherently inaccurate ?

[Otago]

Test strips have a reputation for being inaccurate, is this because the technology is inherently inaccurate or poor implementation (incorrect storage, cheap manufacturing etc..) ? Is an accurate test strip possible ?

 

[Gumbies R Us]

@Randy Holmes-Farley can give you a better answer than I can. From what I understand, they are just cheaply made, and humidity can affect the results as well. This thread below might have some more answers to your question
https://www.reef2reef.com/threads/test-strips-or-not-testing-which-is-worse.1087431/

 

[Randy Holmes-Farley Verified Community Expert]

That's a good question, and I am not certain of all of the answers. But I am confident that the complexities of putting a complicated chemistry test (say, calcium testing) into a test strip makes its accuracy questionable. Even nonstrip tests often have significant accuracy issues.

Test strips are also often made for different industries (say, swimming pools or spas) and thus may not even be made for seawater. That may impact their accuracy.

 

[rtparty]

They certainly aren’t precise and you definitely have to have a keen eye to use them. I ran my old 250g on test strips and a Trident. I trusted the Trident more than the strips but when both were close enough, it was good enough for me.

It taught me how to decipher the strips though because they will say something like alkalinity is greater than 6 but less than 10. Trident would read 8. So it was accurate but not precise