HID with dimable ballast

[CookieMan]

Hi, I am looking at this

and was wondering if it is any good and how the dimable ballast works. Do I just use a regular 400 watt bulb? Any problems with running it at a lower setting? Also, is this a good light? It seems like a great price, which concerns me.

 

[Weaselcracker]

I haven't used an Apollo but I have several dimmable Lumatek ballasts which I've been using happily for more than five years with no issues. To answer at least one of your questions though- for the bulb I just use the one which matches the highest wattage on the ballast. Ie- 1000 watt bulb for a dimmable 1000 watt ballast, 600 for a dimmable 600 ballast, etc.
People talk about issues of the bulbs not emitting at quite the right spectrum or at a lower quality light when run at reduced power.
Somewhere or other last year I found a study on the subject which indicated very little loss of quality in dimmed bulbs. From experience I don't feel it's much of an issue and the dimmable ballasts work just fine.