mome rath
05-11-2003, 9:44 PM
Is there a point past which test strips for NH3, NO3, etc. are no longer viable? Anybody know the chemistry behind these?
JSchmidt
05-12-2003, 8:05 AM
I use test strips regularly. Every brand I've seen is date-stamped for expiration, and my experience has been that they no longer are accurate as that date passes. This is particularly true for strips that measure nitrate/nitrite and ammonia. I have strips for pH, GH and KH that don't seem quite so prone to inaccuracy after the expiration date.
HTH,
Jim