Are expired test kits totally worthless to use?

[Fishy888]

I was looking on Ebay at test kits not long ago. I notice that people are selling expired test kits. Of course they have lower prices. Are expired kits able to test accurately, even if only for a week or 2 past expiry, or are they totally unusable once expired? Thanks.

 

[Arego]

I can't comment for all tests but I can say I've used well expired tests and compared them relative to more accurate tests and they still were in the general range.

Of course using eyes to differentiate colors vs a digital read out will always be a bit suspect and you should have a new one to at least compare the older one against.

 

[saulgoodmannnn]

If it’s a Hannah reagent and it’s expired don’t bother with them totally inaccurate in my experience. Once had one say 350 calc when it was actually 425 and Alk 5.5 when it was 9….With Salifert I tested with an expired Mag kit 10/2020 expiration date and compared with a new one and got the same results. Curious as to what other peoples experiences are….

 

[KStatefan]

In my opinion if it is worth the effort to test why use expired reagents

 

[Dan_P]

I was looking on Ebay at test kits not long ago. I notice that people are selling expired test kits. Of course they have lower prices. Are expired kits able to test accurately, even if only for a week or 2 past expiry, or are they totally unusable once expired? Thanks.

Two weeks expired no problem, but if you plan to use it over the next six months, then I would be so confident about the results. If you had a standard to test the kits against, you could use expired test kits with confidence.

 

[Christoph]

Usually alkalinity and Ca/Mg test kits use very "robust" chemistry, and i would not expect issues after expiration date.

Nitrate and phosphate testkits are a different story.

All the best,
Christoph

 

[Fishy888]

Thank you everyone. I appreciate the feedback. I'm going to get new Hanna kits fairly soon for nitrates and phosphates. I also want to go with Salifert for everything else. I will start by getting cal, alk, and mag in Salifert and the Hanna nitrate and phosphate kits.

 

[Randy Holmes-Farley Verified Community Expert]

Thank you everyone. I appreciate the feedback. I'm going to get new Hanna kits fairly soon for nitrates and phosphates. I also want to go with Salifert for everything else. I will start by getting cal, alk, and mag in Salifert and the Hanna nitrate and phosphate kits.

That sounds like a fine plan to me.

 

[enb141]

Thank you everyone. I appreciate the feedback. I'm going to get new Hanna kits fairly soon for nitrates and phosphates. I also want to go with Salifert for everything else. I will start by getting cal, alk, and mag in Salifert and the Hanna nitrate and phosphate kits.

Yeah, salifert is good for Alk, Ca, Mg, for nitrates and phosphates, unless you have a hawk sight is better to go hanna.

If somebody releases an app to read the colors, instead of guessing, that would be cool.