Test ml question

[lovetoclown]

Probably a dumb question but I'm going to ask for help. I use Red Sea pro test kits as well as two Hanna test. I normally use the the ten ml red sea syringe to fill my test jars. The hanna jars have a line a 5ml. But if I fill my sea syringe to 5ml it's way over the line on the hanna kit jars. So how do I know if my tests are right or wrong when I trust the red sea syringe? :headwally:

 

[bertoni]

Which Hanna kit is this? I have heard that the API vials are marked inaccurately, but I'm not sure about Hanna products.

 

[lovetoclown]

The hanna digital tests for phosphate and alkalinity.

 

[bertoni]

That's interesting, and maybe a bit discouraging. Hmm, I guess I'd trust the lines on the Hanna equipment when using the meters, but not otherwise.

 

[lovetoclown]

Ya now I am second guessing my results.

 

[thegrun]

If I had to pick one I would go with the syringe

 

[outssider]

first off, the hanna Cuvettes have the mark at 10ml not 5ml.

On all my hanna Cuvettes, a 5ml syringe filled twice comes very close to the white line on the Cuvettes.

try a different syringe, maybe the one your using is off. If you get the same result with a different syringe, I'd go with the syringes.

 

[lovetoclown]

You are correct. They are 10ml. But none the less all 3 red sea pro test kits came with a 10ml syringe and they go over the hanna kit lines. I'm gonna try the 1ml syringe 10 times and see where it sits. Maybe see about a different brand syringe too. Thanks.

 

[lovetoclown]

This was ten 1ml syringes. Just a little over the line.

 

[lovetoclown]

One Red Sea 10ml syringe. A lot over the line.

 

[blanden.adam]

I wouldn't worry about that. I took some quick measurements of the images, and even in you 10 mL syringe case you water line is less than 4% away from the marked 10 mL line. That's within the published accuracy of the test kits. Not to worry.

 

[tmz]

Curious: so, I filled the curvette for the hanah using an infant medication syringe . It took exactly 10ml to the line.
Tried the 5ml syringe from one of my Salifert kits; it only took 8ml to the line on the curvette.
I'd fill the curvette to the line when using the hanah.

Perhaps, the test kit syringes Salifert and Red Sea are scaled to deliver 20% less but using a scale easily divided by 10 for user convenience.

Bottom line, I wouldn't use the test kit syringes for anything other than the test they come with.

 

[VJV]

Test ml question

You are correct. They are 10ml. But none the less all 3 red sea pro test kits came with a 10ml syringe and they go over the hanna kit lines. I'm gonna try the 1ml syringe 10 times and see where it sits. Maybe see about a different brand syringe too. Thanks.

Hi. I also have the same test kits from Red Sea as well as Hanna. I can tell you that using the Red Sea syringe I get spot on the 10ml Mark in the Hanna vial. However, you need to bear in mind that you have to align the meniscus of the water with the white line on the vial and you need to drop down to eye level to see this.

The meniscus is the curve that the water surface does in the vial (if you drop to eye level you will see it clearly). You need to align the bottom of that curve with the white line in the vial. To me, that is precisely 10ml using the Red Sea syringe.

This is especially important with the Hanna Calcium as failure to do so will get you substantially skewed results, but will also affect the other tests.

Hope this helps.

 

[tmz]

The 20% variation with the Salifert is way past the meniscus; unmistakeable. Personally, I haven't tried the Red Sea Syringe.

 

[dkeller_nc]

Keep in mind that for a colorimetric test that is a "completion reaction" rather than a titration, a relatively small volumetric error won't make any difference at all. This would be true for tests like nitrate, phosphate and ammonia. Titration tests like calcium, magnesium and alkalinity will suffer from inaccurate volumetric measurements.

The reason it doesn't make any difference for completion reaction tests is that the reagents are formulated in such a way that all, or very nearly all, of the analyte in question (phosphate, nitrate, etc...) is converted by the reagents in the test to a colored end-product. The intensity of that end-product color is either digitally quantitated by something like a Hanna Checker, or interpreted through the side of the vial against a color chart.

Beer's law is the applicable equation; it essentially states that the color intensity is a function of the path length (how much solution you're looking through), the concentration (the factor of interest - e.g., "how much nitrate") and a constant that's a characteristic of the color compound that's formed (called the "extinction coefficient").

Since all of the nitrate in a particular sample will be turned into the colored end-product, and by reading through the side of the vial the path length is the same, adding a little bit more or less water to the test vial won't change the results at all.

Though again, this is not true for drop-by-drop titration tests.

 

[tmz]

Thanks DC. Nice to know.
Many of those tests other than the hanah are read from the top down for higher concentrations , though. So, the volume of fluid looked through would vary if the syringe was off.

Still curious, so I checked the red sea syrniges,the 10 ml syringe and the 5ml syringe against the curvette. It took 10ml in both cases to reach the line. Wonder why the Salifert I have is off 20%. The syrniges Salifert vs Red Sea are from different manufactures, BD and Romed ,respectively.

 

[VJV]

The 20% variation with the Salifert is way past the meniscus; unmistakeable. Personally, I haven't tried the Red Sea Syringe.

Never used the Salifert. Only Red Sea and Hanna. Using the Red Sea syringe the 10ml is right at the bottom of the meniscus as it should be. Good to know that on the phosphate test the actual amount of sample will not skew the results significantly. But the Alk will so again, as per hanna test kit instructions, it is important to get the level right.