Photoperiod
The daily duration of lighting in the aquarium. It influences the photosynthesis of plants and zooxanthellae, the behaviour of fish and the growth of algae.
Detailed explanation
Photoperiod is one of the most important factors for the biological balance of the aquarium. Too much light favours algae. Too little light slows down plants and fades corals.
In planted freshwater aquariums the ideal photoperiod is 6-8 hours for aquariums without CO2 and 8-10 hours for aquariums with CO2. Never exceed 10 hours: there is no advantage for the plants but the algae benefit from it.
In marine aquariums the photoperiod follows a cycle that simulates dawn, full sun and dusk. Modern LED ceiling lights allow you to program gradual ramps. A typical cycle involves 2 hours ramp up, 6-8 hours full power, 2 hours ramp down. The blue LEDs (moonlight) can remain lit for longer 1-2 hours to simulate the moon and make the nocturnal coral polyps open.
The midday break (turning off the lights for 2-3 hours in the middle of the day) was a technique used to combat algae. Today it is no longer recommended because it interrupts photosynthesis without real benefits.
Photoperiod also influences fish behaviour. Many species have circadian rhythms that depend on the light/dark cycle. Turning lights on and off suddenly causes stress. Gradual ramps simulate sunrise and sunset and give fish time to prepare.
In the refugium the photoperiod is typically inverse to the display: the macroalgae are illuminated at night to stabilise the pH.
Light power is not compensated by duration. It's not correct to think "I have dim lights so I keep them on 14 hours". This approach only benefits algae.
Coralia Lab allows you to configure the photoperiod in the aquarium's technical data sheet and the AI takes it into account in the evaluations.
Coralia Lab monitors this parameter with AI diagnostics. Tank Score alerts you when a value moves outside the recommended range for your aquarium.
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