outside air

hi all . i have my closet almost ready to go . my question is . i have a exhaust fan the goes in the flex pipe and a carbon filter to keep the closet cooled off and kill of the smell. i also got a 400w hps/mh light w/blaster . i have mylar for the walls . i also have a fan to blow the air around the cloest . i have a few questions .
1. do i need to hang the blaster or is it ok to keep it on the floor outside the closet ?

2. do i need to put in a vent to the outside so air from outside can get into the closet ? if so should i use another exhaust fan and put it backwards so it draws air from the outside into closet .

3. i was told best temp for the closet is around 76 degrees is that right . if so would the fan and the exhaust fan be enough to keep the closet that cool ?

4.should i get a fan that just blows on the 400watt light to keep the blub cool ?

5. last question when starting from seeds should i run the light for 14 hours . also when plats and growing is 14 hours on and then 10 hours off good for growing . then when i want to flower i go 10 hours on 14 hours off ?

thanks to all who reply for your time and for your help ..i hope this works out for me ........

1. floor is fine.
2. No if you are blowing air out then air will be drawn in.
3.76 is good. Start it up and you will find out.
4. flex pipe from light hood to exhaust fan to carbon filter and out the closet.
5. leave lights on for 24/7 or 18/6 and when ya flower 12x12

ok.......so

1. Ballast....not blaster. But thats neither here nor there. i set mine on a piece of metal that is slightly elevated to promote air circulation...they get hot. I wouldn't set it on the ground.....or a piece of wood....not that it gets hot enough to combust anything...but just to be safe.

2. YES! you need to cycle air through...plants like fresh air just like we do.

3.keeping it cool its trial and error....your setup might work...or its might not, you are going to have to wait and see.

4. wouldn't hurt... i don't think its essential. maybe look into a cooltube...might help with cooling if its a issue

5. A lot of people use 18/6 for veg and 12/12 for flowering....

Hope that all helped.