False Reading From Hannah Checker or High PO4

[Davisc1293]

I have cleaned the vials and i ordered more reagent but it ended up being the same lot number. I do notice a lot of very fine partciles in the sample when putting it back in. ive tried waiting longer but does not all disolve. I dont think it is from the reagent causing the particles. any idea someone mentioned a filtered syringe which i did order and will try.

 

[gbroadbridge]

Try cleaning your vials in acid.
If the machine reads the standards right it has to be the vials or the reagents.
For me it was the vials.

Well it could be stuff off your skin if the sample or reagent touched your skin. Soap would do it. The test is sensitive.

 

[WVNed]

Well it could be stuff off your skin if the sample or reagent touched your skin. Soap would do it. The test is sensitive.

I had the same problem. I had to clean my vials more than I usually do.
In RODI and Vinegar.
Then the readings came back down.
My false readings where consistent to the vial.

 

[Davisc1293]

Well it could be stuff off your skin if the sample or reagent touched your skin. Soap would do it. The test is sensitive

I had the same problem. I had to clean my vials more than I usually do.
In RODI and Vinegar.
Then the readings came back down.
My false readings where consistent to the vial.

Thanks guys, I Will soak the vials in some vinegar and a good rinse before trying the filtered syringe tomorrow while wearing some gloves. lol

 

[gbroadbridge]

I had the same problem. I had to clean my vials more than I usually do.
In RODI and Vinegar.
Then the readings came back down.
My false readings where consistent to the vial.

Me too, I clean them with citric acid which I buy in bulk from amazon. Quite a few have been broken during the cleaning process, I should invest in Hanna with the number of test kits I've collected.

 

[gbru316]

This is the salifert phosphate high sensitivity test so the scale should be halved. But like i said i never use this test because i find i very hard to read and the hanna has allways been consistent

Using photoshop to get the RGB values of your sample and reference card, then determining average percent error of the sample compared to the reference, you're somewhere between 0.25 and 0.5, closer to 0.25 according to Salifert.

 

[gbroadbridge]

Using photoshop to get the RGB values of your sample and reference card, then determining average percent error of the sample compared to the reference, you're somewhere between 0.25 and 0.5, closer to 0.25 according to Salifert.

Lol, I did that too, back before I posted post #30.

At the end of the day, 0.25 or 0.50 is pretty irrelevant as both are too high.

Thanks for making the point that colour analysis and correction is important.

Ideally, these colorimetric tests should be read under 6500k lighting

 

[Davisc1293]

One thing im also wondering about now is the fact the standard i used to verify was noticeably purplish but Even when my tank was testing close to .5 ppm the sample has no noticeable color to it.

 

[gbroadbridge]

One thing im also wondering about now is the fact the standard i used to verify was noticeably purplish but Even when my tank was testing close to .5 ppm the sample has no noticeable color to it.

The chemisty is complicated and I assume Hanna worked that out in their colorimetric tests.

The Hanna checkers measure color.

The bottles of color tinted water water they sell as references do not measure the test you perform, they simply measure that the color matches what they assume is a reference level.

If you wish to accurately check phosphate, you can mix your own solution, and then test it with a Hanna checher.

My experiments indicate it is reasonably accurate.

 

[Davisc1293]

The chemisty is complicated and I assume Hanna worked that out in their colorimetric tests.

The Hanna checkers measure color.

The bottles of color tinted water water they sell as references do not measure the test you perform, they simply measure that the color matches what they assume is a reference level.

If you wish to accurately check phosphate, you can mix your own solution, and then test it with a Hanna checher.

My experiments indicate it is reasonably accurate.

In your experiments did your samples that measured over .2-.5 have a noticeable tint of any color anywhere near as noticeable as the reference vials they sell?

 

[gbroadbridge]

In your experiments did your samples that measured over .2-.5 have a noticeable tint of any color anywhere near as noticeable as the reference vials they sell?

Well yes.

Hanna are a test manufacturer of excellent reputation in commercial use, and I rely on their test standards daily.

If you're asking if I I trust their hobby grade test checkers, then yes I do within their limits of measurement accuracy and assuming a hobbiest can test accurately .

Unfortunately, a lot of tests carried out by aquarium owners are lacking in precision and accuracy so the results are often suspect.

 

[Davisc1293]

Well yes.

Hanna are a test manufacturer of excellent reputation in commercial use, and I rely on their test standards daily.

If you're asking if I I trust their hobby grade test checkers, then yes I do within their limits of measurement accuracy and assuming a hobbiest can test accurately .

Unfortunately, a lot of tests carried out by aquarium owners are lacking in precision and accuracy so the results are often suspect.

Again, since recent icp came back at .05 the same day hanna tested .18 after bringing it down from .5. But even when my tank tested .5 the sample looked pretty clear to the eye no noticeable tint of any color just the fine particles i mentioned.

 

[Randy Holmes-Farley Verified Community Expert]

In your experiments did your samples that measured over .2-.5 have a noticeable tint of any color anywhere near as noticeable as the reference vials they sell?

Again don't stress on the color of the reference vials. They could be green, as long as they absorb the right amount at the right wavelength.

ALL those vials test is the electronics, not anything to do with the actual phosphate test chemistry.

 

[Davisc1293]

Ok great. that does make sense, so the color of the sample could still look clear but test over .5ppm. Just very confused with this tester latley and even more so now with the icp test and nyos kit.

 

[Randy Holmes-Farley Verified Community Expert]

Ok great. that does make sense, so the color of the sample could still look clear but test over .5ppm. Just very confused with this tester latley and even more so now with the icp test and nyos kit.

Not sure what you mean by clear. 0.5 ppm phosphate will be clearly colored in a phosphate test.

 

[Davisc1293]

Not sure what you mean by clear. 0.5 ppm phosphate will be clearly colored in a phosphate test.

I mean other than looking a bit "chalky" with a ton of fine particles in the sample they have never had a distucual tint or shade of color even when testing as high as .49 i think was the highest i saw. Its been testing about .15 as of now but still looks "clear" no noticeable color change.

 

[Randy Holmes-Farley Verified Community Expert]

I mean other than looking a bit "chalky" with a ton of fine particles in the sample they have never had a distucual tint or shade of color even when testing as high as .49 i think was the highest i saw. Its been testing about .15 as of now but still looks "clear" no noticeable color change.

lots of particles in the test will lead to false high readings. I assume they are not there from your water sample being tested?

 

[Davisc1293]

Im not sure if the particles are directly from the tank or undisolved reagent or some kind of percipitation. Ive tried wating longer then the 2 minutes to let more disolve but dont think the particles are soluble. Someone suggested filtered syringes so i have some sterile filters and syringes coming from amazon today

 

[gbru316]

Im not sure if the particles are directly from the tank or undisolved reagent or some kind of percipitation. Ive tried wating longer then the 2 minutes to let more disolve but dont think the particles are soluble. Someone suggested filtered syringes so i have some sterile filters and syringes coming from amazon today

You're gently shaking for 2 minutes before testing? I hold mine between thumb and fingers and just flip upside down - rightside up for 2 minutes. Have never had any appreciable particles.

 

[Davisc1293]

I started getting weird high reading after starting silicate dosing. Ive read the silivate particles can effect the test but only at high levels which my silicates have never been above 2ppm and icp just came back at just over 1ppm si. But yes i shake for 2 minutes and as mentioned i tried waiting longer but the particles dont seem to be reagent particles or soluble.