"~ jan" wrote:

On Sun, 1 Jul 2007 17:32:03 CST, Kurt wrote:

Out of curiousity- what is the reality of how much an out-of-date (say 2
years) all-in-one litmus kit that had been kept in dark container, would
be off. Would certain readings tend to me more off than another?

I couldn't tell you. In the KHA program they showed us how to make a
control solution (one you know is a certain ppm/pH, etc.) and test it. I
don't go to that extreme, but I do periodically have the other KHA check my
water, to see if my readings are similar to his.

My experience with the strips was when they hit the expiration date they
were DOA. I almost killed an $80 fish, back in my less experienced days,
because of the brand of strip I had, had just passed the expiration date.
Has the chart you compare the strip to, also been kept in the dark? They do
fade with time.

Short answer, YMMV, as will brand & type. ;-) I wouldn't chance it after
the expiration date has been reached.

Btw, I went to my local hardware store and here were a bunch of Pond test
strips left out in the heat, rain, cold (and looked like it), pass
expiration date, still for sale. Buyer beware. ~ jan
------------
Zone 7a, SE Washington State
Ponds: www.jjspond.us


I buy a new test kit every year. Ammonia, nitrites, ph & kh. Considering the
investment in pond and fish, it is cheap insurance.


San Diego Joe
4,000 - 5,000 Gallons.
Koi, Goldfish, and RES named Colombo.