How long do API test kits last? Do they go bad??

[Chefken]

Measuring for Phosphate. When I test my tank and tap I get a color reading that does not match anything on the card....I get a straight yellow reading like a 0 ammonia....the card zero reading has some green in it......Not a match at all. Have had the test kit about 3 years but it has only been used 5 or 6 times. Virtually full bottles. Thank you!!!!!!!!

 

[kno4te]

It’s on the bottle. Check ur date.

 

[Rocksor]

if the exp date has rubbed off, you can see the manufacture date in the last 4 digits of the lot number

e.g. knote's nitrate bottle picture shows it was made in july 2014 and expires 5 years later

Low ph, high ph, ammonia, nitrite, nitrate, kh expire 5 years after manufacture date

gh, copper, and phosphate expires 3. years after manufacture date

 

[Chefken]

thanks....my bottles say nothing. Guessing it is shot.