All blue LEDs will create PAR. It's the level of intensity that will determine how much PAR is seen. If that PAR level is too high, then corals will be kept "awake", and will be very irritated. This is one reason I don't condone the use of high power LEDs, and recommend that lower power 5/8/10mm LEDs be used for lunar lighting.
They really are for our own enjoyment though. There has been speculation that lunar lights will help trigger spawning events, but this seems to be more common in fish rather than corals. The only corals I've seen actively spawn with any kind of frequency is Sun Corals, and Blue Snowflake polyps. Neither have required lunar lighting to do so.
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