I agree with bender, you cant use a bulb with a different wattage than the ballast,
and for the cabinet size you have,just go with the 400w and you'll be fine.
If you have a vented hood it would be best,to vent out the heat directly from the source.

QB
QueBud Reviewed by QueBud on . Question about 1000hps and ballast OK....this may well be dumb question....but here goes... I am heavily considering the investment in a 400 or 1000 watt HPS.... I need to know...if I bought a 1000 HPS and ballast... can I use this set up down the line with a 400watt HPS bulb... eventually I need to set up a cabinet and I know a 1000 would burn up my plants in a cab aprox. 20 inches x 48 inches x 52 inches(height).... Prices as they are...I am wondering if just investing in the 1000 might be worth it.... it would be if I Rating: 5