How long does water last before testing

[wireform]

Have this question in my head for the longest time. Searched but haven't found a clear cut answer. So here it goes: I take a water sample using a 16 oz water bottle. How long can I wait (the longest) to still have accurate testing and if not which ones will last and which won't.
Thak you
Allan

 

[Newdude]

FC decreases per it's UV exposure

Ph is skewed by temperature and can be aerated by rattling around in the cup holder of your vehicle.

The rest shouldn't be affected for a reasonable time, but I'd shake it anyway when the time comes.