Actinic lights are primarily for aesthetic appeal on aquariums. They are not an efficient source of light for plants, and have virtually no red light, so I would avoid them. The 6500K bulbs are ideal, and the 10000K bulbs should also work pretty well. I would consider these options: 1) Stick with what you have. 2) Use the 10000K VHO's, but not the actinics. 3) Combine the above two options. 4) Use the MH's, provided they are not overly blue bulbs like 20000K's or something. If the plants are still fairly small and you can position them all within six inches or so of the bulbs, then one of the first two options should work. If you need more light, I'd consider one of the last two options.

You don't specify the wattage you want, nor the size, nor if you need dimmable. That being said, we use the 15-20-23w (I think that's it) (50-100-150 equivalent) spiral from GE, which is 2700K and enjoy it just fine. Don't know the CRI, but can see them at Wal-Mart. For dimmable, we use Greenlite R40 23w floods, which are 2700k and CRI 82 (the website below will say 3000k, but it's wrong). We also use their 23w dimmable sprirals, which are also 2700k and CRI 82. I personally think that Greenlite makes the best around, and their dimmable technology smoothly goes down to 20% light. But, I have never seen them in a store and have always ordered them via 1000bulbs.com or the the link below. What I find annoying now is this... because of Wal-Mart's HUGE push into CFLs, and with CFLs being made in China, the availability of dimmable CFLs has dropped to zero in the past 30 days. It will pass, but I want them now... not in January! Here is a link that might be useful: Imagine Energy

I believe they say that because the ballast does give off some heat. The trapped heat will shorten the ballast life. I don't know if there's any way to tell how long. You'll know the ballast is going when the bulb goes on, then shuts off 1-3 minutes later (at least that's how ours have died). I can't see it being a fire hazard because a regular bulb gives off much more heat than a CFL ballast. And, when the ballast dies, current doesn't flow any longer.

Even fluorescent lights with dimming capability often have problems at low settings. The rather expensive dimming ballasts for 4 foot tubes do not go all the way to 'off' using the dimmer. If the current in a fluorescent tube gets to low it will not produce enough UV to excite the phosphors enough to carry over even from cycle to cycle at 120 Hz (the arc in the tube is re-established on each half of the 60 Hz voltage cycle).