Do Hanna Checkers have different colour LEDs?

[Garf]

I only have one checker, the Phosphate LR. The LED colour is green, same as the casing, as it happens. Am I right in thinking other checkers have different colour LEDs to take readings more effectively, depending on the colour change of the solution under test?
I bring this up as I’ve tried using the API nitrate test kit in the Hanna LR and appear to get useful numbers, as long as I can get around to converting the reported number (but trending is ok for me at the minute).

Cheers.

 

[Dan_P]

I only have one checker, the Phosphate LR. The LED colour is green, same as the casing, as it happens. Am I right in thinking other checkers have different colour LEDs to take readings more effectively, depending on the colour change of the solution under test?
I bring this up as I’ve tried using the API nitrate test kit in the Hanna LR and appear to get useful numbers, as long as I can get around to converting the reported number (but trending is ok for me at the minute).

Cheers.

Yes, Checkers can have different color LED’s.

The nitrate and phosphate Checkers all have green LED’s. You can use one of the phosphate Checkers to measure the color intensity of the nitrate tests, though the number you get is not in ppm but a relative absorbance number that is proportional to ppm. Checkers meant to measure light colored solutions do not work so well with deeply colored test solutions and vice versa.

 

[Garf]

Yes, Checkers can have different color LED’s.

The nitrate and phosphate Checkers all have green LED’s. You can use one of the phosphate Checkers to measure the color intensity of the nitrate tests, though the number you get is not in ppm but a relative absorbance number that is proportional to ppm. Checkers meant to measure light colored solutions do not work so well with deeply colored test solutions and vice versa.

Excellent, thanks Dan. I’ll probably knock up a stock solution with potassium nitrate to make a rough calibration curve, so I may call on you again, if you don’t mind

 

[Dan_P]

Excellent, thanks Dan. I’ll probably knock up a stock solution with potassium nitrate to make a rough calibration curve, so I may call on you again, if you don’t mind

Happy to advise. @taricha and I make it a habit of using Checkers to measure all sorts of colored solutions.

 

[Malcontent]

Not only that but you can often find the wavelength in the specifications.

 

[Garf]

Not only that but you can often find the wavelength in the specifications.

Oh, yeah, 525nm for both Phos and Nitrate, never thought to check that, thanks.

 

[taricha]

The checkers come in
470 nm blue
525 nm green
575 nm yellow-ish
610 nm orange

 

[Red2143]

I just asked a similar question about using the copper checker and then saw this post

I also have phosphate ulr. If that is the same wavelength as nitrate how would I go about using the phosphate ulr to test nitrate? I have api reagent that maybe could be used also?

 

[Garf]

I just asked a similar question about using the copper checker and then saw this post

I also have phosphate ulr. If that is the same wavelength as nitrate how would I go about using the phosphate ulr to test nitrate? I have api reagent that maybe could be used also?

Dunno, I’m gonna give it a try.

Happy to advise. @taricha and I make it a habit of using Checkers to measure all sorts of colored solutions.

My potassium nitrate turned up. Looks like 1 gramme in 1 litre of freshwater gives 614ppm. I’ll split this to 61 ppm and see if the colour is too deep for the hanna to read with API as the kit. If so I’ll split it again until I can get an API reading. I can definitely get a reading at 0 ppm, just the upper limit I’m not sure of as yet.

 

[Garf]

Quick rethink, I need to make a saltwater solution, as there is a difference in the way the kit reports fresh and saltwater. I’ll make a 6140ppm solution and spike new saltwater from there, then try to generate a curve.

 

[Red2143]

I've been so focused on using the copper checker for api nitrate I forgot about this post and the fact that phosphate ulr and nitrate are the same checker wavelengths. Could Hanna nitrate reagent be used with the phosphate ulr once a curve is established? Seems it would solve the api batch variation in the other thread?

 

[Garf]

I've been so focused on using the copper checker for api nitrate I forgot about this post and the fact that phosphate ulr and nitrate are the same checker wavelengths. Could Hanna nitrate reagent be used with the phosphate ulr once a curve is established? Seems it would solve the api batch variation in the other thread?

The cost of the nitrate reagents put me off going down that route.

 

[Red2143]

The cost of the nitrate reagents put me off going down that route.

Aside from the price, do you think using Hanna reagents would conceptually work and it's just a matter of figuring out the appropriate dilution to register on an ulr device?

 

[Dan_P]

Dunno, I’m gonna give it a try.

My potassium nitrate turned up. Looks like 1 gramme in 1 litre of freshwater gives 614ppm. I’ll split this to 61 ppm and see if the colour is too deep for the hanna to read with API as the kit. If so I’ll split it again until I can get an API reading. I can definitely get a reading at 0 ppm, just the upper limit I’m not sure of as yet.

Looking forwards to a happy ending

 

[taricha]

Aside from the price, do you think using Hanna reagents would conceptually work and it's just a matter of figuring out the appropriate dilution to register on an ulr device?

Right. The Hanna NO3 will work fine at 525 nm where the phosphorus / phosphate checkers operate.
Some dilution will be required for the higher color stuff like you said.

 

[Red2143]

Right. The Hanna NO3 will work fine at 525 nm where the phosphorus / phosphate checkers operate.
Some dilution will be required for the higher color stuff like you said.

Thank you. Is there a rule of thumb/starting point dilution based on range (0-10, 11-20ppm,etc). Seems like the dilution would be pretty high given how light the phosphate colors are.

 

[Dan_P]

Thank you. Is there a rule of thumb/starting point dilution based on range (0-10, 11-20ppm,etc). Seems like the dilution would be pretty high given how light the phosphate colors are.

I can tell you what I do. I play with it for awhile. It’s sandbox time.

I first look at the color intensity of the highest level of the test intended for the Checker. This gives me a very rough idea about highest color intensity of the new kit I am going to use in the Checker. You’ll have to run a test with the new kit to see what it does. If your Checker handles light to medium intensity color, try the new kit at 5 ppm, more or less based on your judgement. See what happens.

Have fun. You can’t break anything except the rules

 

[taricha]

If I'm guessing, I might think a 1/10 dilution would be a place to start.
(1mL reacted sample near the end of the hold time, added to 9mL distilled water in a hanna cuvette.)

Like Dan says, trial and error after that.

 

[Garf]

Anyone see a benefit with setting “C1” after the addition of the yellow dye (API nitrate). I’m assuming it just sets the lower limit on the curve. I’m thinking it may improve resolution of the colour change rather than measuring the yellow as part of the overall colour change.

 

[taricha]

Anyone see a benefit with setting “C1” after the addition of the yellow dye (API nitrate).

Agreed.
I said the same to red2143 in a message.
"Here's the best solution I didn't think about in the thread.
Once you add reagent 1, cap and invert 10 to mix.... use THAT yellow as the c1 blank.
If the meter stays on for 10 minutes you have plenty of time to add reagent 2, shake 60 seconds, wait 5:00 minutes, then use that reacted sample as c2."