When you read a test result, where should the vial be held?

[glb]

When I do tests that rely on color comparison, eg Salifert nitrates, I've always wondered if the vial should be held slightly above the color chart or be set on top of it. When the vial is placed on the chart itself, the number is always higher. What is the correct way to read these tests??

 

[Labridaedicted]

I set it on top of the card and look down through the tube. Always got pretty accurate results that way.

 

[glb]

I set it on top of the card and look down through the tube. Always got pretty accurate results that way.

Thanks.

 

[wkscott]

Depends on the test manufacturer and the specific test or if it's regular or low range in the same kit. Follow the manufacturer's instructions.
In any case, the vial should be right on the color chart without light coming in from behind it.

 

[saltyfilmfolks]

also squint your eyes a bit and look for the contrast between the colors and not the actual color change.

 

[glb]

Depends on the test manufacturer and the specific test or if it's regular or low range in the same kit. Follow the manufacturer's instructions.
In any case, the vial should be right on the color chart without light coming in from behind it.

Thanks. That makes sense.

 

[glb]

T

also squint your eyes a bit and look for the contrast between the colors and not the actual color change.

That's the hard part about these tests. They're my least favorite kind because they're hard to read.

 

[glb]

T

also squint your eyes a bit and look for the contrast between the colors and not the actual color change.

That's the hard part about these tests. They're my least favorite kind because they're hard to read.

 

[Lionfish Lair]

From salifert....

 

[wkscott]

From salifert....

This is exactly what I was referring to in my post above, I was just too lazy to pull out my test kit's instructions.