sorry missed the part where you mentioned you dosed flourish. Anyway, id cut back the light to only 6 hours a day and maybe start dosing individual ferts instead of an all in one style like flourish. That is just way to much light for way to long especially without co2 of any sort (diy or pressurized) or dosing specific separate ferts. just out of curiosity what type of lighting is it? PC? MH? T5?