how inaccurate is API testing kit?

[mjaquarium02]

hey saltwater fish gang,

i was just wondering how inaccurate is the API testing kit? i have a fish tank that i’ve been testing with API but I’ve read from past experiences that Ammonia is usually super inaccurate, but what about the rest? PH, Nitrite, and Nitrate? are those a bit better? I found a LFS that tests water with Red Sea and Hanna test kits. Is that better?
What testing kit do you guys recommend?

thanks!

 

[taricha]

From a freshwater standpoint - API isn't actually *inaccurate*, it's just that the colors are really hard to discern - Hanna checkers basically do it for you rather than having to go "mmm, I dunno, that looks a little purple, a little blue...."

This is also my view.
if you use API reagents and run them through devices that can measure color electronically (hanna checkers, colorimeters, spectrophotometers) then you come to the conclusion that API tests are actually very repeatable and precise.
except API Nitrate. their NO3 reagents vary too much lot to lot for any comparison from one lot to the next to be reliable.

My current favorite ammonia, nitrite and pH tests are using API reagents.