Originally Posted by dr2b
That's why I was unsure, my one plant requires 12 hours of light a day minimum - so I actually forgot the correct length without plants lol.
If this is the case you need a higher-wattage light, not a longer photoperiod. Many planted tank sites recommend 8 hours max and anything else is an invitation for algae. For bettas I give a max of 6 hours of light since they like their 'dark-time'. In fact, Lou bites his tail whenever the light is on so I keep it off as much as possible.