Parameter Testing: Lights on, or off?

[hockeyhead019]

Curious if this has been talked about before or if people have common practices and a technical reason behind it.

I've always tested with my lights on, usually about mid-way through the cycle since I feel that's when the tank is most "stable" for the day. However with pH swingsand PO4 consumption possibly by active algae with the lights on I'm curious if my system would differ if I test before the lights come on.

FYI my system is a small 20g setup so I doubt this point has much applicability for those on larger systems.

 

[wolfthefallen]

IMO its more important that you always test about the same time everyday, this way you can track the changes over time more reliability. pH will change through out the day. Normally it will be lowest right before the lights come on and peak for an hour so at the brighest point of your lights. Thats if intensity changes through out the day. If the lights are just the off and on type it will peak probably mid way through the light cycle and hold until the lights go off.. There are some other factors with pH such as O2 levels in the air, and alk. this is all rough.

Biggest is just tracking your measurements so you can adjust accordingly, do all your checks at the same time(s). Be this daily or weekly.. It is all about consistency