Test Kits

[westiemarble]

Having spent the last week dosing my Mg levels from 960 up to 1200 I decided to check my container of fresh salt water and found it to be at 1020 (D&D H2Ocean salt and 200L water made 6 days ago).

However, I've just noticed my Salifert Mg test kit has an expiry date of 'May 2009'.

Might be a daft question but is the expiry date critical?

Cheers

 

[omega59]

indeed i always wondered about the dates, same with medications.

 

[kj23502]

ooohhhh this is a tough question. Need a chemistry major to answer this one for us. It depends on the chemicals the test is made of and how stable they are over time. It's basically a matter of the chemical properties changing over time. A slight change could easily alter the test results. I'd pay attention to the dates esp if you're using them to detect levels of stuff you are dosing.

 

[AK77]

Its probably better to use a test kit that is in date. Like KJ said, chemical compounds can become unstable and break down after a certain time period and may be affecting the results. For the sake of something that costs £10, its better to know that what the test kit is telling you is accurate rather than run the risk of overdosing an additive and nuking your tank, taking £100's worth or livestock with it.

 

[westiemarble]

new test kit ordered - will let you know the two sets of results!

 

[SkiFletch]

It's really a problem with water vapor. The expiration dates are "suggestive" and not absoloute. Even if the reagents are a little "off" it'll still be close enough to tell you if your aquarium is close or far. And Magnesium is really a value that you just want "high" so just go ahead and use it

 

[ALW]

I wouldnt any chemicals/compounds that is it is over a month expired. So in your case i wouldnt use it. As Ski say ^ expiry dates are given as a guide to the effectiveness of the compound in question. Within the expiry it should be operating to near 100%, but gradually falling over time. Outside the expiry the compound in question can drop to only 10% effective and so not give accurate results.