Test kits Pond vs Fresh water

[delmargray]

I recently read a thread where it stated that a pond ph test kit would expire before a fresh water ph test kit would, anyone know why? Also will there be a difference in results between the two for PH, Nitrite, Ammonia, Nitrate?

[nigelchapman]

You know that this test kit pond really gives so much accurate results then any other but here is a problem as mentioned in this thread that its really expire before its given time.