Expired Salifert Phosphate Test

[tnc112105]

Just realized my kit expired several months ago. Can I trust the results?

 

[Crabs McJones]

If it's expired I wouldn't trust it. Although it is just a phosphate kit. If it was alk or calcium i'd definitely steer clear. If it was a couple weeks you could probably continue to use it, but several months i'd just get a new one

 

[Randy Holmes-Farley]

No way to know without checking it.

Get another kit and test them side by side. If the results seem close enough for you, then you can use both.

 

[tnc112105]

I guess I kind of already knew the answer to that one.

Just wondering if anyone is aware of what the reagents are in the kit and how stable they are. At my workplace, there are expiration dates on the reagent grade water, so...

I guess I can use this as an excuse to finally get a Hanna checker!

 

[Hubert J. Farnsworth]

for comparison, i found and tested some PO4 reagent envelopes for my hanna checker that expired in 2016 and they yield the same results as my unexpired reagent.

 

[JimWelsh]

Just wondering if anyone is aware of what the reagents are in the kit and how stable they are.

Many phosphate test kits use a liquid reagent containing ammonium heptamolybdate in strong acid solution (usually sulfuric, sometimes hydrochloric) and another crystalline/powdered reagent that is ascorbic acid. These ones always produce a blue color (perhaps pale yellow at the lowest PO4 concentration), with the intensity being correlated with the phosphate concentration. In my experience, they are remarkably stable when stored in the dark at room temperature.

 

[Rybren]

I found an old Salifert Phosphate test that expired in 2018. I ran a couple of tests with it along side a brand new AquaForest Phosphate test.

The results, according to my eye, were the same. I don't trust my eyes and often use the colour comparison feature of the Aquarium Notes app. Using the app, the results were close enough to being the same.

 

[Cory]

Same here one that expired in 2016 I still use it. Its the same blue as a hanna checker.

 

[Dan_P]

Just realized my kit expired several months ago. Can I trust the results?

If you had a standard to test, you would not have to rely on the expiration date. You might find kits last a long time.

 

[SuperDodge]

I just tested this last week. I pulled out two old Salifert kits that were 3 years out of date. The Salifert phosphate kit appears to be good compared to my Hanna Checker.

 

[Randy Holmes-Farley]

Same here one that expired in 2016 I still use it. Its the same blue as a hanna checker.

The N95 mask I've been wearing to bring food to my daughter in quarantine (coming back from Australia when her semester of study abroad was cancelled mid term) expired in 2005. Hope the pores have not opened up too much. lol

 

[NS Mike D]

for comparison, i found and tested some PO4 reagent envelopes for my hanna checker that expired in 2016 and they yield the same results as my unexpired reagent.

Still using my 2016 Red Sea. I should increase my testing and use it up faster so the new bottles don't expire as well

 

[SuperDodge]

Still using my 2016 Red Sea. I should increase my testing and use it up faster so the new bottles don't expire as well

That's the sad part of this, right? If we were actually testing enough then we wouldn't have all this expired stuff!

 

[Cory]

The N95 mask I've been wearing to bring food to my daughter in quarantine (coming back from Australia when her semester of study abroad was cancelled mid term) expired in 2005. Hope the pores have not opened up too much. lol

Lol id be worried about that. But something is better than nothing? I should clarify i dont use it for a precise reading like i do with the Hanna checker, but just to see if po4 register's or not so im not starving things.