yea their are switchable ballast that can use both.

that night/on day/off thing works great if your schedule can do it. only thing then would be to make sure their is no light leaks. it will be more evident at night. but i would say get your light and turn it on for 12 hours then check the heat in their. if its pretty good. then great don't need exhaust.


but intake you still do need to keep fresh O2 in da room. unless "this option is awesome if your heat stays down" is to use some Co2 in your grow room. will do alot for your plant its whole growth.

http://cheaphydroponics.com/cart/ind...ewCat&catId=40

thats a link to some squirrel cage duct fans. i like squirrel cage the best since they are a little cheaper then the in line fans. but dats me = )

but like i sed earlier if you don't get much heat in their. think about a co2 system. its about the same as a good fan minus the gas.
907PokeSmot Reviewed by 907PokeSmot on . Help me set up...please guys :( I have a little shed outside measuring 4'x4' and 6'high. I plan on using a 400w ballast which can take both halide and sodium. I will properly insulate and lightproof first. I am just unsure on ventilation. I am presuming that because i am outside i will experience less heat (i'm in the UK!) but am aware that i will still need some fresh air passing through. I guess i am just unsure on how much heat a 400w sodium bulb produces and am really confused on fans and filters etc. Can i get a Rating: 5