Do Water testing Kits go bad?

[TXKev]

I have had my test kits ever since I setup my tank 2.5 years ago (I probably do not test frequently enough.) I tested my tank today, and everything came back perfect. Amonia, Nitrite, and Nitrate were all 0. Ph was 8.2. Normally I would not think much about it but, as I mentioned in another thread, I had a cyno breakout this week. I do not have a phosphate test, which I know could cause the cyno also. So I decided to test my new nano that I setup on Friday. I only tested the Amonia, Nitrite, and Nitrate. They were 0 except for Nitrates that were between 5 and 10 ppm. That does not sound possible even though half the rock was from another tank and I used "Live Sand". The brand of my test kits is Aquarium Pharmaciticals Inc. Probably not the best ones to begin with.

Thanks,
Kevin

[captexas]

I've seen some that have expiration dates on them so my guess is yes some of the chemicals can go bad over time.

[Noodle]

Putting them in extreme temperatures will also prematurely shortern the life of the test kit.