dimmable ballasts don't require a corresponding bulb to the wattage output. also they will only run th wattage their set at. ie even tho its a 1k ballast with it set at 400w its only pulling 400 watts. i know this cause i've tested it with an ammeter. which is a meter that measures amps. hooked the meter around the live and fiddled with the adjustments starting at 400 watts and increased incrementally and as i dialed up teh wattage teh amps corresponded. i just want to put this out there as im seeing soo much misinformation about dimmable ballasts. also ive read about spectrum changing wavelength. not true. the wavelength is determined by the bulb. the wattage determines how much power gets to the bulb. the bulb will still operate the same just not as bright as there is not the same amount of power reaching it.
that aside...
Im not sure about burnig the 1000 on the 400 setting tyler,im not sure anyone knows how they are designed to be used but here is a blurb directly from solis teks website on their 1000w dimmable ballast:
-4 step dimming: SolisBoost - 1000W - 600W - 400W.
-Metal Halide (MH) & High Pressure Sodium (HPS) Lamps
-2 power cords included
-Soft Start Technology
-Powers 1000w, 600w, 400w lamps.
-Constant Power Factor 99.9%
- 8.92 AMPS @ 120v / 4.46 AMPS @ 240v
since your only running a 4x4 area and 1 light, moving up to a 1k is definitely what you should do. conversely tho. 2 600's would double your light footprint and only for an extra 200 watts.
i just went from a 8x10 room with 3 1k's to the same 8x10 room with the 4 6's and then a 5x 10 room with another 2 600's. im so confident my yield will increase i'd bet the farm, as tehy say.
Im not sure about burning the 1000 on the 400 setting tyler,im not sure anyone knows how they are designed to be used but here is a blurb directly from solis teks website on their 1000w dimmable ballast:
-4 step dimming: SolisBoost - 1000W - 600W - 400W.
-Metal Halide (MH) & High Pressure Sodium (HPS) Lamps
-2 power cords included
-Soft Start Technology
-Powers 1000w, 600w, 400w lamps.
-Constant Power Factor 99.9%
- 8.92 AMPS @ 120v / 4.46 AMPS @ 240v
There seems to be alot of confusion on this matter.