How Long to keep lights on?

Hello everyone.. My goal is to have a heavily planted tank.. it is already pretty heavy but in the end there is going to be a LOT of plants.. I Have CO2 and 4 watts of light per gallon.. I dont have an algae problem right now.. but right now I am leaving hte lights on for 16 hours a day.. and 8 hours of darkness... is this a problem for the fish>? Should I be giving them a longer light cycle?? I have one gourami, 2 otocats, 2 zebra danios and 2 african dwarf frogs.. with such plants there is a lot of hiding places for the ones who dont like light..
thanks

 

well as long as there's no algea problems and lots of shade then i guess it could be ok. i don't leave mine on for more than 10 hours a day and i think that's pretty much the norm. correct me if i'm wrong

 

Im sure once my plants start to really grow and get outta control I will be down to 8 hours a day hehe.. but until then im gonna make these babies grow!!