How long should the aquarium lighting be on?
At the equator there is a maximum of 12 hours of daylight. Therefore this is the maximum amount of time any tropical fish aquarium should be lit. Anything more will cause the algae to grow.
But it is worth considering other factors that affect the duration of sunlight in nature. At dawn and dusk, the brightness of the sun is weakest. Using controllable LED lighting, you can simulate dawn and dusk cycles in your aquarium. Cloudiness can therefore affect the intensity of the sun, as can precipitation. If your fish and plants come from wooded areas, they will undoubtedly experience shade from the forest canopy above them.
Because of these factors, live aquarium plants and corals need even eight hours of light a day to survive. If you have problems with algae, the first thing you need to do is to adjust the lighting so that it does not exceed eight hours a day.
Therefore, in the case of marine tanks, aquarium keepers often set the lighting to fade in and out gradually during the day.They start and end the day with blue lighting that increases to its whitest setting at noon to simulate the bright midday sun in the tropics.
If your lighting can’t be controlled, plug it into a simple lighting timer. Set it to turn on and off at the same time every day. If you don’t have live plants or corals and only have tropical, cold water or saltwater fish, you can even turn the lights off when you’re not looking at the fish. They will also be fine with the ambient light in the room. The result will be much less algae growth. Which you just need to remove.