Woah, you've got rosenbergi in the tank? They'll eat your plants if you aren't careful... And they're actually food over in singapore
Barbeque them with chilli
My advice would be to use lights. Simply because you can't control the sun in the even you have algae problems. Another thing. There is no noticable difference between aquarium lights and normal household brands. Both kinds support photosynthesis.
Though in your case if you plan to plant. You'll need about 110 watts of T8 fluorescent lighting. A more economical solution would be to get T5 tubes, they're 50% brighter(meaning you use only 80 watts) and last 4 times longer(T8s have to be changed every 6 months for good growth)