Well, a comments here:
1) the tank gets sunlight, which is hard to control in terms of light level. You're probably getting too much light for the amount of CO2 that is in the water.
2) not dosing fertilizers may be helping the algae if your plant growth is being limited by lack of nutrients. I don't see any major deficiencies in the pictures, but they are a bit fuzzy. Regardless, vigorous plant growth tends to deter algae. However, if the plants are CO2 limited rather than limited by fertilizers (NPK, etc), this won't make a huge impact.