the only options i can think of is by replacing the ficture itself with a vho or pc Mh combo if you dont want to add a canopy then you can go retrofits.your halide fixture covers too much area to just try and add something to work with it.and still make it look good IMO
you could try the MH Pendant Fixtures. They just clip on the back of hte tank and hang over the water. Don't think you can actually put VHO or even PC in there, you have no room left.
