Moonlight in the aquarium: why the lunar cycle matters — and how every GHL luminaire reproduces it
Reef life follows the moon. Most aquariums ignore it: the night light, if there is one, is the same every night. Here is why the lunar cycle is worth reproducing, and how it works with every GHL luminaire.
Why the moon matters underwater
Once a year, in their spawning season, many stony corals release their gametes in the same few nights — often a few nights after a full moon. Numerous reef fish, crustaceans and polychaete worms show the same lunar periodicity in their reproduction. Recent research indicates that an important cue may not simply be the full moon itself, but the sequence of light and darkness around it, including the dark hours between sunset and moonrise in the nights that follow.
Moonlight also shapes nocturnal life in a less obvious way: visually hunting predators can make use of a bright moon, while many prey organisms alter or reduce their activity under brighter nights. Either way, the animals respond to the light level — and to its change over the month.
That is the point: what matters is not a night light as such, but its rhythm. Waxing to full moon, waning to new moon, and around new moon virtually no lunar illumination. A fixed night light, identical every night, provides none of that. A moon simulation that follows the lunar cycle reproduces an important part of the natural nocturnal light rhythm that corals and fish experience in the wild.
What a real moon simulation does
ProfiLux controllers have always computed the moon phase from the calendar date. Nothing to program, nothing to keep in sync: you define when and how bright the moonlight shines at full moon, the controller scales it night by night following the real cycle.
For breeders and research applications, ProfiLux offers an extended moon mode: the period length and the date of the full moon can be set freely, so a lunar cycle can be run independently of the real sky. Where spawning is the objective, a ProfiLux can additionally run a seasonal temperature and main illumination profile over the year — moon, temperature and season from the same controller.
How it works with your luminaire
Every GHL luminaire can produce moonlight — including earlier generations such as Mitras LX6 and Lightbar 1. Mitras LX7, LX7 IL and LX8 do it on their own; Mitras Lightbar and Mitras Slimline do it under ProfiLux control.
Mitras LX8 — the LX8 has a dedicated moonlight channel with its own moonlight LEDs. Intensity and color of the moonlight are adjustable, and further color channels can be assigned to the moon function as well. The lunar cycle runs on the luminaire itself, standalone or under ProfiLux control.
Mitras LX7 and LX7 IL — the moon function is assigned to any of the nine color channels. The moon phase simulation is built in and follows the real lunar calendar — no controller required.
Mitras Lightbar 3 and Lightbar 2 — alongside the high-power LEDs, every Lightbar carries RGB LEDs for exactly this purpose. Connected to a ProfiLux, assign the moon function to one or more of the RGB channels — done. No additional fixture, no extra cable.
Mitras Slimline — under ProfiLux control, the moon function can be assigned to one of the Slimline’s own channels. The companion Mitras Slimline RGB adds three separately dimmable color channels and gives you more options: free choice of moonlight color and dimming to even lower levels, plus dawn effects. Both connect to the Mitras Slimline Splitter Dimmable, which receives the ProfiLux control signal and powers up to two Slimline plus one Slimline RGB from a single power supply.
The controller
Lightbar and Slimline need a controller for dimming, and every ProfiLux runs the moon phase simulation: ProfiLux 4, 4.1, 4e and 4.1e with 32 illumination channels as full aquarium controllers, the ProfiLux Mini WiFi with 24 illumination channels plus pH and temperature control, or the ProfiLux Light WiFi as a dedicated light controller with 24 channels. All of them are operated via the GHL Connect app, the built-in web server or GHL Control Center.
Tonight
If you own a Mitras LX7 or LX8, or a Lightbar or Slimline on a ProfiLux: open the illumination settings, assign the moon function to a channel, set the moonlight window. From tonight on, your aquarium follows the lunar cycle.
