Expired test kits

[Cory]

I have a lot of expired test kits. They seem to produce the same results as when new. However, my salifert alk test is expired, and getting low in acid. It produces diferrent results than Hanna and Api.

Why would a test kit expire? What happens to them chemically when they expire?

 

[Salty1962]

The chemicals that determine you test break down with age. If it were me, I would not rely on expired test kits.

 

[Cory]

The chemicals that determine you test break down with age. If it were me, I would not rely on expired test kits.

How does it degrade? Oxygen?

 

[Randy Holmes-Farley Verified Community Expert]

What I would do is to get a new kit, and if it matches the old one, keep using the old one until it no longer gives similar results to the new one.

As to why: various chemicals break down, such as oxidation of organics (dyes, chelators, etc.. Some (*like pH indicating reagents or calibration fluids) may go bad by absorbing CO2, altering the pH. Others may go bad by evaporation, altering concentrations.

 

[Cory]

What I would do is to get a new kit, and if it matches the old one, keep using the old one until it no longer gives similar results to the new one.

As to why: various chemicals break down, such as oxidation of organics (dyes, chelators, etc.. Some (*like pH indicating reagents or calibration fluids) may go bad by absorbing CO2, altering the pH. Others may go bad by evaporation, altering concentrations.

So in alkalinity dyes such as saliferts, it wouldnt be good to try and pump the vial to get air bubbles out, as this may cause unnessary air to enter it?

 

[Habib(Salifert)]

The dye is in a dropper bottle. Not sure if I understand your question.

Was that kit ever used before or was it still unopened?

 

[Cory]

The dye is in a dropper bottle. Not sure if I understand your question.

Was that kit ever used before or was it still unopened?

Yes it is in a dropper bottle. The test kit is 3 years old, but expired recently. The test kit has been used many times.

It reads lower than api and hanna. Possibly due to evaporated acid? What strenght acid does the kit use? Can i use the same acid from my salifert strontium, or magnesium test kits?

 

[bmac16]

Just ran into this problem as I had an old salifert mag kit that I tried using. The old test was 885ppm, and I brought a sample to my LFS to dbl check it for me and he measured 1200ppm.....needless to say I just got a new kit

 

[Habib(Salifert)]

There is no acid in the two other kits

If you plan to get another kit (regardless which brand) then I would compare it again and you might want to decide it is still good and use it further.

 

[Habib(Salifert)]

Just ran into this problem as I had an old salifert mag kit that I tried using. The old test was 885ppm, and I brought a sample to my LFS to dbl check it for me and he measured 1200ppm.....needless to say I just got a new kit

That is due to evaporation. If the cap is not closed properly after use then evaporation would take place. More critical if the reagent bottle get's more empty.

I don't have the exact figure here but the evaporation, if properly closed, is approx. 0.2% per year.

FWIW, I intend to post a thread in the coming days with a simple way to check for evaporation ocassionally if the need be there.

 

[bmac16]

That is due to evaporation. If the cap is not closed properly after use then evaporation would take place. More critical if the reagent bottle get's more empty.

I don't have the exact figure here but the evaporation, if properly closed, is approx. 0.2% per year.

FWIW, I intend to post a thread in the coming days with a simple way to check for evaporation ocassionally if the need be there.

I was pretty sure the test kit was bad. It was expired and the dropper was a dark yellow, but I figured I would give it a try.

 

[Randy Holmes-Farley Verified Community Expert]

So in alkalinity dyes such as saliferts, it wouldnt be good to try and pump the vial to get air bubbles out, as this may cause unnessary air to enter it?

I'm not sure how it is designed, but the less exposure to air the better for many organics.

 

[Cory]

There is no acid in the two other kits

If you plan to get another kit (regardless which brand) then I would compare it again and you might want to decide it is still good and use it further.

Thanks. Curious why your test kits dont have hazard symbols on the bottles or warnings to keep away from children? I would appreciate that in the future.

 

[Habib(Salifert)]

Thanks. Curious why your test kits dont have hazard symbols on the bottles or warnings to keep away from children? I would appreciate that in the future.

There is info on back of the box and in the instructions.
With a few exceptions, our reagents are not classified as hazardous. Those that are have symbols on the labels.

 

[Cory]

There is info on back of the box and in the instructions.
With a few exceptions, our reagents are not classified as hazardous. Those that are have symbols on the labels.

Okay. So if my child ate one of the reagents, no harm would be done?

 

[Habib(Salifert)]

Okay. So if my child ate one of the reagents, no harm would be done?

Even if a reagent is not classified as hazardous, one is not allowed to say it is safe.

 

[AlexStinson]

Okay. So if my child ate one of the reagents, no harm would be done?

Shouldn't it go without saying that test kits should not be anywhere near children? Aside from toxicity issue, common sense would dictate that the glass, dyes, and often sharp syringes would be not child safe.

 

[Salty1962]

Shouldn't it go without saying that test kits should not be anywhere near children? Aside from toxicity issue, common sense would dictate that the glass, dyes, and often sharp syringes would be not child safe.

+1!

 

[Cory]

Shouldn't it go without saying that test kits should not be anywhere near children? Aside from toxicity issue, common sense would dictate that the glass, dyes, and often sharp syringes would be not child safe.

Common sense yes, but so was hot coffee that someone at macdonalds sued for because it didnt say "caution hot", when they burned themselves. Right?

 

[Cory]

Even if a reagent is not classified as hazardous, one is not allowed to say it is safe.

Okay, I understand. But we are talking big amounts of chemicals right? Not pesiticides on fruit in small quantities for example. There is no harm in putting warning labels on something that could be dangerous. I think it would be great if you put on the bottle some form of child saftey thing. Like a child lock bottle, or a sticker or print saying it could be bad. Btw i think i might have been the guy a long time ago that motivated you to put alk standards in the box. But it could be good no?