suggestions for fixture/ballast purchase

I have been having major algae issues in my DT because someone suggested switching from 420/460 dual actinic bulbs to dual 6500/10000 daylight bulbs. I quickly learned that those bulbs are excellent for growing algae.... but not in my DT. I am going to switch back to new actinics and do not want to just throw out the daylight bulbs because they are only a few weeks old. My question is does anyone know of a good fixture and ballast at good price for a single bulb. The bulbs are square pin (4pin) dual 6500/10000 bulbs 130 watts.

Thanks!

 

I have not seen any single bulb in that size.