After actually seeing the tank in question yesterday, lighting alone is not going to do it. The HOB filter with a passive carbon bag, though helping with circulation, is quite frankly is not going to cut it. There is no real means for nutrient export, the substrate alone cannot support the bio load. The addition of some live rock and a skimmer would improve water quality tremendously.

As a side note, the 4 anenomes (though of the same species) in that small a water column is likely not helping matters. Some sort of clean up crew in there to help remove detritus and stir up the substrate can only be helpful as well.