Is it possible to use expired pH tests?

[Lanpenn]

Hello everyone!

Since I am trying to investigate why my Lemna sp. and Salvinia minima growth is poor in my aquarium, I will probably need to test the pH (it would be good to have GH and KH tests, but they are expensive in the country and I do not know if it would be necessary to have a simple Betta splendens bought from a farm shop...).

I have a pH test that expired on October 1st, 2024 (a Brazilian brand, Labcon). The composition is as follows: bromothymol blue, sodium hydroxide, and distilled water.

Is it better to buy another pH test? In any case, concerning the plants' issues, should I ask about them here or in another thread?

Thank you for your attention!

 

[anewbie]

You can use it but depending on a number of factors the regent might be chemically unstable and less reliable. There is really no way to tell. I think i've read this as being more of a problem with nitrate tests; on the bright side if it was kept on the cool side it isn't that far out of date only a few months.

Still my experience with submersed plants gh would be more useful. Having acidic water will increase the amount of co2 in the water colum but that is less relevant to floating plants where the leaves are mostly emersed. gh of course would give a hint on mineral content though not which minerals.

 

[MaloK]

I have a ph test 35 years old here that is ready to compete with anything you got last week.

But... It wasn't stored in the glove box of a car.

 

[AJ356]

They say anything is possible if you truly put your heart and soul into it

 

[Lanpenn]

Well, today I bought another pH test. I measured and I got 7.5... the same value I obtained with the previous brand. Is it good for the plants I have?