Help please with reading Salifert test colours …

[peterhos]

Hi All

I think I am being stupid. When measuring for phosphate/nitrate none of the colours to my eye really match up to the colours on the card provided.

I am much happier at moving the vial around on the card to see which colours on the card do/do not show through the test sample. If I then choose a colour on the card which does not show through the sample as too dark then is that the colour I should be looking at?

If I hold the vial up to the light and look at the colour card then I can see a good match, but if I place the vial on the card I find matching difficult. Did I explain that well enough?!

Anyone else have the same problem? Are the Hanna testers idiot proof?

Thanks all.

 

[Super Fly]

I read the vial and color chart outdoors during daylight, the natural sun light makes a huge difference in deciphering the colors.

 

[peterhos]

I read the vial and color chart outdoors during daylight, the natural sun light makes a huge difference in deciphering the colors.

No sun here in the UK recently! Do you match by holding card and vial to the light or by placing the vial on the card, which is what mucks me up? Thanks again.

 

[Super Fly]

No sun here in the UK recently! Do you match by holding card and vial to the light or by placing the vial on the card, which is what mucks me up? Thanks again.

oh yeah, I forgot about UK weather (BTW, my family visited London last summer and absolutely loved it there!)... I match by placing the vial on the card. However the artificial indoor lights tend to skew the vial colors a bit so if you really can't read it outdoors then I would hazard a guess. And if trying to guess the color starts getting annoying, I would recommend trying Hana tester which will give u # readings w/o having to guess the color.

 

[peterhos]

Thanks again. Hanna sounds the way to go…

 

[kbnh]

If you hold up and look at the vial from its side it, you’d have to match the color then divide that number by 10, so if it looks like 25 when you are looking from the side it is actually 2.5. When looking from the top then you don’t have to divide, this is their “low range mode” for when your nitrate measurement is 10 or less

 

[bvanfish]

I have found trying to use a light bulb depending on the "temperature" of it can really impact my readings. A more yellow bulb can make something look vastly different than your phone flashlight.

I try to just get to natural light doesn't have to be sun necessarily but just natural light

I like my hanna for the ALK but it sucks having to buy reagent all the time. Salifert is nice and works well for me

 

[Garf]

Thanks again. Hanna sounds the way to go…

I’ve never really bothered about phosphate. My salifert was light blueish whenever tested, that’s was ok for me. Recently bought a Hanna to do some hobby tests. Thrown the salifert in the bin, turns out it was miles away from even near the truth, combined with aging eyes.

 

[peterhos]

Excuse my stupidity … again… but if I look through the vial holding it a fraction off the card I get a much lighter colour than if the vial sits on the card. Also, for comparison I have just tested water from a new RO unit which shows a minimal colour, but certainly not zero.

 

[peterhos]

Yes, ageing eyes may be part of it for me too …LOL.

 

[workhz]

Someone mentioned it above but here are the instructions:


Specifications
SALIFERT NITRATE TEST KIT INSTRUCTIONS
Low range: 0.2 - 10 mg/L (ppm) as nitrate. Medium range: 2 - 100 mg/L (ppm) as nitrate.
Procedure for both ranges:
1. Fill test vial with 1mL of water.
2. Add 1 level scoop of NO3-1 powder (compress this powder against the inner side of the
powder container).
3. Add 1 level scoop of NO3-2 powder and swirl gently (do NOT shake) for 30 seconds.
4. Let it stand for 3 minutes.
5. Color comparison:
Medium Range:
Place the test vial on the white part of the color chart and compare colors looking from the TOP. Use diffuse daylight when comparing colors.
If the color corresponds to a value lower than 10mg/L nitrate then it might be better to compare colors as shown for the low range (see below).
Low Range:
If the medium range color comparison procedure gave a reading lower than 10mg/L then you can use the low range procedure. This will increase the accuracy.
The color for the low range procedure has to be compared by looking through the SIDE of the test vial.
The white part of the color chart has to be held firmly against the opposite side of the test vial. Use diffuse daylight when comparing colors.
The color is, by looking through the side, 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.