I think in general, the answer is that it's best to test around the same time of day. There are multiple factors to consider though:
Water Change - Some parameters may be higher just after unless you're dosing (ex. Iodine).
ATO - Just after your ATO dumps in a R/O, your parameters may be lower.
Dosing - Just after dosing those parameters may be higher.
Lighting - Absolutely affects pH, Alk, Cal.
I run my light cycle 12 hours on, 12 hours off. 10-10 because well, that's when I'm likely to be home and viewing the tank.
I run my Alk/Cal dosing (24/7 every 30 minutes) in the same 12 hour cycles (2 different programs) with daytime dosing approx. 2.4 x nighttime.
So when do I test? If manually testing I test Cal/Alk at either 10am or 10pm (sometimes both if I'm looking to adjust dosing). I turn off my ATO 30 minutes ahead and test approx. 25 minutes after my last dose. I do my water changes on Thursdays so for everything else (Ammonia, Nitrite, Nitrate, Phosphate, Magnesium, Salinity, pH, Iodine) I test Saturday morning around 10am. I do it Saturday morning because I tend to be free that morning! ;Woot
I now have an Alkatronic though so I'm hoping my OCD will be able to let go and get to the point that I'm just manually testing on Saturday mornings. ;Nailbiting
Water Change - Some parameters may be higher just after unless you're dosing (ex. Iodine).
ATO - Just after your ATO dumps in a R/O, your parameters may be lower.
Dosing - Just after dosing those parameters may be higher.
Lighting - Absolutely affects pH, Alk, Cal.
I run my light cycle 12 hours on, 12 hours off. 10-10 because well, that's when I'm likely to be home and viewing the tank.
I run my Alk/Cal dosing (24/7 every 30 minutes) in the same 12 hour cycles (2 different programs) with daytime dosing approx. 2.4 x nighttime.So when do I test? If manually testing I test Cal/Alk at either 10am or 10pm (sometimes both if I'm looking to adjust dosing). I turn off my ATO 30 minutes ahead and test approx. 25 minutes after my last dose. I do my water changes on Thursdays so for everything else (Ammonia, Nitrite, Nitrate, Phosphate, Magnesium, Salinity, pH, Iodine) I test Saturday morning around 10am. I do it Saturday morning because I tend to be free that morning! ;Woot
I now have an Alkatronic though so I'm hoping my OCD will be able to let go and get to the point that I'm just manually testing on Saturday mornings. ;Nailbiting
