Lighting time in an aquarium?
How long should the aquarium light remain switched on every day?
concerning the lighting time, there are rather different opinions among both aquarists and aquarium literature. Where most aquarium fish and plants originate from, the day length is a rather constant 12 - 13 hours.
I therefore favor an according daily lighting time of 12 - 13 hours. Since, according to my experience, the background behind this question is usually to reduce annoying algae growth by a several hour "lighting lunch break": Aquarium care with few algae ("algae free" is not possible in a biological/scientific sense and would not even be desirable) is possible also without such a break, balanced conditions provided!
Dr. Bodo Schnell