maybe too many ferts. i got green water and loads of other stuff when i first started my tank and then as if a blessing from god everything stoped and i havent had a problem except small stuff. i contribute mine to not fully cycled tank.
i have more light now than i did then. co2 then and now. and i use a litttle less fert but also have a lot more plants.
one more note i have 6 23 watt sprial cfls and still no probs.
if i had to guess i dont think u have that many plants to be using that much fert