Usually when you turn an LED toward the blue settings the PAR will lower simply because youre turning some of the LEDs down. Most current LED fixtures are more than powerful enough to provide acquit PAR even at super blue settings.
All of my LEDs are turned WAY down. Like 20-50% of full power.
I have it set to be bluish from 8am to noon, ramping up in power and blueness. Halides come on and LEDS are mostly blue supplements until 6pm when the halides go off. Then the LEDs go to a more white setting and ramp slowly back down in power and go blue toward the night.
Its the future, we have the technology. Make your tank look the way you want it.
