plz help with my ventilation

hi i have a room in my celler. measurements are: 5f length x 4f width x 6f height. im gona use the Atami Wilma 8 Pot Hydroponics System and Sun System VII 800 Watt Super Spectrum light. i like this light coz it uses both ends of the light spectrum of MH and HPS 2gether.i dont mind paying xtra for bigger buds. i dnt know how im gona ventilate, they is no gaps or windows in this room, the only opening is the door from my celler to the room (it used to be a back door leading to yard, but has been bricked up) i want to ventilate away from celler. so i plan on knocking a brick out and running a vent pipe inside a fake drain pipe, up 2 the top of my kitchen roof( its an extension, so its not 2 high). but how big does the hole have to be? and how do i do all this.its the only thing i cant work out. oh and anuva thing do i have to get fresh air in, if so should i make 2 holes in the wall? 1 hole 4 air in n 1 hole 4 air out. plz help thanks

The problem with that light is yea it's cool, but depending on flowering and veging one light is gonna be wasted pretty much. You'd be better off buying a 600Watt system with a switchable ballast (can go MH or HPS) and buying a MH bulb and a HPS bulb. Just my opinio, though. Otherwise I don't fully understand the cellar thing. How do you get into it?

basically the back door in celler used to lead out under utility room, but some1 has built a wall to make it a room same size as utility room above. i thought about useing a light that you can switch between mh n hps but i read that mixing the lights 2gether makes a better grow. does this sound right?

Thats an awesome idea with drip drain incognito idea you got brewing there. Idealing i would have the intake on the door somehow as i would imagine that door is on an opposite or adjacent wall to the brick wall planned for the exhaust. You will need to create negative pressure in the room to pull air in so and exhaust fan will be your best bet. Depending on how high your roof is you will need a pretty strong fan that works good against some higher static pressure. I would recommend a squirrel fan as brick is rather dense and you have to worry less about the noise generated from it than someone with a fan in a cabinet or closet.

You are working with 120 sq feet there. I would say a 500 cfm squirel or centrifigual fan would be more than sufficient. If you did want a quiter fan you can go with an inline like an S&P fan. How large in diameter or square is the exhause going to be? How large are the bricks?

The intake can be passive and utilize the door or the brick wall but if using the brick wall you will need to remove a seperate brick as you dont want to exhause what you have just brought in. What are outside temps like in your basement and outside the brick wall will also be a deciding factor.

You will hear on alot of threads that you need an passive intsake twice the size of an exhaust which i believe has no validity as long as your exhause fan can handel the higher SP created by the smaller passive intake.

Good luck and if you get me a drawing or some more measurements i can give you a better opinion...

I would stick with the light as well as that can always be upgraded later if you are not pleased with the results. I would spend the money on the exhaust fan personally as if dont have enough fresh air and temp regulation your grow can go to shit alot faster than the difference between the 600 hps and your current light will make.

Also I am rather new here but i wouldnt recommend taking everones advice as them knowing what is best. Alot of people do have scientific and logical minds on here though and don't just repeat incorrect opinions thay heard or read elsewhere.

Also I just checked out your link to your grow system your using. that will not take up your 120 feet. I would partiton that area off, keeping the height of course. This will enable you to raise lower the pressure alot quicker with a smaller fan. And that light is near perfect for that 8 pot system in terms of size...