I can't believe that if your feeding twice a day that your nitrates aren't through the roof? If they aren't, it's just because your algae is feeding on them. It's a false negative on your nitrates. Most people I come across feed every other day to keep their water from being nutrient rich. Also, since you have such an abundance of algae I assume your not doing partial water changes often enough. If you insist on running your aquarium the same way get SNAILS. My Turbo snails keep my tank virtually algae free! Good luck! Next battle- ICH to be continued...
14 gal biocube salt
1 orange zoo polyp colony, 2 toad stool (small), 1 umbrella leather (large), 2 pulsing xenia, 1 star polyp colony, 7 blue mushrooms, snails, pep. shrimp, 3 blue legged hermits, 2 onyx percula clowns