my dad says it's light to, but it's actually too much ammonia, which makes too much nitrites, which makes too much nitrates, which too little plants can absorb, so algae grows by eating the nitrates. it's easier to cut back stock (i'd never do that until my parameters wiggle) put more plants (sometimes expensive and unruly) or just buy a scrubber and scrub for algae once a week and sweep it off plants with your hand/net/turkey baster
If you put you tank in direct sun light it will probably make the problem worse as the algae can photosynthesise better.
You can also by a product called Green Away here in the UK that clumps all the suspended algae together so the filter picks it up, clears the water in an hour or so. Its worth having a look around your LFS for a similar product.
I had this problem what u do is when ur not at home dont have the light on and when u get home u can turn the light on in the tank. It worked for me i dont have as much algae now! Or u could by meds!
