Water test

[chrisg]

What is the best time to test water in a reef tank?

 

[mojoreef]

Midway into the lighting cycle

Mojo

 

[NWDiver]

I would add that it is nice to check pH just before the lights come on, and just before they go off. This will give you the pH "swing" that your tank has every day.

-Todd

 

[Herefishyfishy]

Whenever the shears are sharp. Wait, that's when to prune shrubs.
Test the water wehenever you get an opportunity and if you can pick your time, mid day for single tests.
If you have lots of time and test kits, do as Camera-Todd suggests