PAR meter questions

[Billgasser]

What percentage if any does water flow affect your PAR readings?
How much does a “Kraken like lid” decrease the PAR?
When measuring PAR do you work around the lid and leave the flow on?
Do you measure it at the max your reef sees doing the day?
Thank you

 

[liddojunior]

I always use a par meter for setting my lights
A lid does change the PAR. I measured with the pumps on and the moving surface doesn’t seem to change par that much. Light passes through and the surface moving just changes the angle that light refracts and reflects.

You should test par at every different configuration of your lights. Like why are you running for one hour at a different intensity if you don’t know what that intensity difference is, and the ratio of par to light percentage isn’t exact.
The par meter is so you make the percentages of your light and schedule with real data as rationale

 

[WhatCouldGoWrong71]

I have not noticed flow making a difference. I’m well over 75 times display turn over, well over. But I have also never shut my flow off and did measurements. That’s not realistic. My flow might drop back 15% overnight, but for the most part, the washing machine is running 24/7.