Active intake Active exhaust question

Hello good people of RU I am constructing an 8K closed vent air cooled lighting. I will pulll air from another room through the lights and directly out of the room never coming in contact with room. The room is 150 sq ft. I will have a 4 inch fan bringing in fresh air from another room at the front of the room at the back wall I will have an 8 inch(720 cfm) pulling the old stale air through a carbon filter and out of the room. My question is do the intake fan and exhaust fan have to be on for the whole 12 hour light cycle? Or should I run them on timers? I'm trying to create negative pressure. Ty in advance for the help

I too would like to know the best way to create negative pressure needed..

The best way to create negative pressure is to have a big ass exhaust fan. You don't need an intake fan.