API TEST

[wilkinson]

A quick question about API test

So the label says to let sit for 5 minutes before doing the readings .... I tested my water today on my almost cycled tank.
After 5 minutes my readings where 0 ammonia .25 nitrite and 20 nitrate. for the first time i did not empty and cleaned the test tubes right away instead i went grocery shopping with my girl.
when i got back ( about 1.5 hour later ) i came to empty and clean the test tubes and to my surprise my readings where now .25 ammonia .50 nitrite and 50 nitrate ??????????
Im not sure what to make of this .

Any ideas anyone.

 

[jtalley]

The chemicals continue to react if left alone, but they are not the results you want. I believe the tests are based on a reaction rate, such that certain amount of reaction will be caused by a certain concentration in the prescribed time.

 

[muffywrx]

Thank you for asking this question. That clears things up. lol.

 

[jtalley]

The tests measure the reaction of your water with the reagent (API Liquids). The color change is an indication of the amount of reaction that occurred.

Based on their chemicals, API knows the reaction rate per ppm of what you are testing.

So, we want the reaction amount, and they know the reaction rate per ppm.

(Reaction rate) / ppm = (Reaction amount / Time) / ppm

If you introduce a sample of say X ppm, and use the prescribed time:

(Reaction rate) / ppm = (Reaction amount / Time) / ppm * X ppm * Prescribed Time

We have the reaction amount which is calibrated against their colors. And voila, you know the X ppm.

Not a chemist though, just my thought process.

 

[wilkinson]

The tests measure the reaction of your water with the reagent (API Liquids). The color change is an indication of the amount of reaction that occurred.

Based on their chemicals, API knows the reaction rate per ppm of what you are testing.

So, we want the reaction amount, and they know the reaction rate per ppm.

(Reaction rate) / ppm = (Reaction amount / Time) / ppm

If you introduce a sample of say X ppm, and use the prescribed time:

(Reaction rate) / ppm = (Reaction amount / Time) / ppm * X ppm * Prescribed Time

We have the reaction amount which is calibrated against their colors. And voila, you know the X ppm.

Not a chemist though, just my thought process.

Well put explication thank you