Testing time??
 

Is there a prefered time to do your water tests? Will the readings be different first thing in the morning versus after the lights have been all day?

Generally the only big fluctuations will be with your PH, it will drop during lights out due to a build up of CO2 as photosynthesis has stopped, limiting O2 production. All other typical parameters we test for should remain fairly constant.

OK was just curious since I leave for work at 5:30am and always test late at night after work.