Measuring Par - Wavemaker/Pumps: on or off debate

[RaymondL]

So I can't seem to settle on what is correct here when measure PAR values with a meter in a tank. Some say to ensure the water is as still as possible while I'm hearing the other case that PAR should be measured with the actual environment which the light is in - this means not turning off any pumps/wavemakers.

So what's right here?

 

[zheka757]

Lol, try measuring with lights on and off also.

 

[aaron186]

when I measured with my powerheads on I was getting a fluctuating number moving around 10-20 par from the shimmer. When I turned it off I was still around 10-30 of what I was getting with them on. Personally I don’t think a range of 10-30 is going to make any difference in the long term success of your reef. I would do whatever is easier for you. Perhaps do both as it takes a few extra minutes