PAR Meter Reading Fluctuation

[MolaMola]

Help! Second time I am dealing with major fluctuations in PAR meter readings, for instance a range of 70-150 or 105-280. What could I be doing wrong?
I have adjusted the sensor eyeball direction in diff locations with no better results.
Most problematic tank has Kessils and quite a lot of shimmer. Do you turn off return pump? Or circ pumps if they disturb the water surface?

 

[JVU]

I turn all wavemakers off and my return pump down to the lowest setting (DC pump). If I couldn’t control the return pump setting, I’d either turn it off or point the nozzle down so that I’m getting minimum surface agitation. It’s the surface ripples that cause the PAR fluctuations.

 

[MolaMola]

I'll do that. Thank you for the advice.