Salifert Nitrate Testkit

[cbleehk]

Hi,

I've been reefing for a couple years but only today did I notice the instructions says you need to "press the white part of the indicator paper against the back side of the vial to look at it from the side".

I've always just kinda float it behind the vial but it seems like pressing against it makes the color show up much darker. So my previous reading of say 2.5ppm is now around 5ppm.

I just wanted to get some reassurance that pressing against the vial & having a darker shade is in fact the correct way.

Thanks!

 

[Ron Reefman]

Hi,

I've been reefing for a couple years but only today did I notice the instructions says you need to "press the white part of the indicator paper against the back side of the vial to look at it from the side".

I've always just kinda float it behind the vial but it seems like pressing against it makes the color show up much darker. So my previous reading of say 2.5ppm is now around 5ppm.

I just wanted to get some reassurance that pressing against the vial & having a darker shade is in fact the correct way.

Thanks!

I'm probably not the guy you want to have answer this question, but since nobody else has, I'll give you my advise.

First, I've been in the hobby for 15 years and I quit testing for nitrate more than 5 years ago. I do test for Ca, alk and occasionally for Mg. And if I see an issue, I may test for ammonia. I use API kits most of the time and if I get a real flier of a result, I'll double check it with a Salifert test kit. But I don't even have a Salifert nitrate test kit and my API test kit expired years ago!

OK, that said, IMHO it's less important about how you do the reading than that you do it the exact same way every time. Holding a white backer up to a test tube can/will change how light or dark the fluid in the test tube looks. But so will the direction of the light. Lit from the side looks different than if the light is behind you and directly parallel to your line of sight into the test tube. And even the type of light can make a difference. A warm tungsten light gives it one shade, a cold white fluorescent bulb will make it a different shade and direct sun will make it even a different shade.

Just do it the same way every time and try to do it the way the directions tell you to do it.

Good luck and I hope that helps a little?

 

[Gareth elliott]

I have a really hard time reading the salifert nutrient test kits. But you are doing it correctly.
Fwiw The nyos kit i found the easiest to read.

 

[RumMnky]

From memory.. if you look at the salifert through the side you divide by 10 for the low range.. maybe someone can confirm..

 

[Retro Reefer]

Assuming your doing the high sensitivity test yes you need to press the color chart against test vial, also lighting is a factor when taking readings so I make sure I’m using the same light for every test.. manufacturer recommends diffused daylight for best results.

 

[Waters]

You are doing it correctly....it has to be pressed against the side, which does make it significantly darker.

 

[RumMnky]

From Salifert instructions:
For Low Range:
If the medium range color comparison procedure gave a reading lower than 10 mg/L then you can use the low range procedure to increase accuracy.

The color for the low range procedure has to be compared by looking through the SIDE of the test vial.

The white portion of the color chart has to be held firmly against the side of the test vial. Use diffused daylight when comparing colors.

By looking through the side, the color is amplified by approximately 10 fold. For this reason, you have to divide the color chart values by 10. For example 2 will become 0.2 and 50 will become 5.

 

[cbleehk]

Thanks guys. I am taking the exact same procedure with the lighting and reading except the "pressing hard against the back" part. The light I have is a diffused LED strip under my kitchen counter. My guess is the LED is at 4000K which is much warmer than daylight. I don't think it changes the color of the pink too much but the darker shade after pressing against the back has an obvious difference of one shade darker. So I was keeping my tank at 2-2.5ppm but it was actually 5ppm or so. It's still all within range but good to know if it does gets out of hand I'd know earlier.