I have heard 10-12 hours of light a day is good for a planted aquarium.
Is it better to have 10-12 consecutive hours, or should one break them up for example 5 on 5 off etc.
Why would it be better ?
As you know plants have evolved to photosynthesis while the sun shines. Depending on the species of plant that can be as long as 15 hours. Plants have the ability to handle cloudy days and days where sunlight fluctuates do to variable cloudiness. but nowhere on this planet do plants have 5 hours on followed by a break followed by 5 more hours. Always take your cues from your natural surroundings.