Bubble tips can do very well without halides, I have noticed them thrive better with them however, but still they are not needed. You can conceivably do well with the combination that you have. I have had them live and split with less light than you have now. My preference here for lighting over a 75 and bubble tips would be a 440 watt VHO setup, but your 6x65 should do fine. Just try to have enough rock work for it to climb to about 2/3 up the water column so that it can decide where it would like to be.
Thomas