I would check the following:
1. Phosphate level: Shouldn't be zero for a planted tank, but shouldn't be higher than 1-2ppm.
2. Lighting: How long are your lights on? You might want to consider dialing them back.
3. Feeding: Are you overfeeding your fish? Excess food becomes nutrients for the algae.
For filtration, if your phosphates are high, get a pouch of Seachem Phosguard. It works very well, just make sure to follow the instructions *precisely*. I would also recommend adding a micron filter to your filtration, either a 50 or 100 micron pad will work. I use these on my tanks when needed to polish the water: Coralife Pure-Flo Micron Filter Pads
The best part is that they can be washed and re-used, so the packages lasts forever.