help with evacuation/circulation fan settings May 27, 2012 12:50:42 GMT 7 Quote Select PostDeselect PostLink to PostMemberGive GiftBack to Top Post by cpbobby on May 27, 2012 12:50:42 GMT 7 I have a 10 gal terrarium and installed a new evacuation/circulation fan with the new plex lid.In addition i drilled a 2 7/8 holes to allow new air to come in faster while the 4 1/2 fan pushes out the existing air. As of now it comes on 2 times when photocycle is off and 3 times when the photocycle is on. Every time it activates it runs for 30 minutes since that is the minimum time the time allows me to set. Iirc the times are 9pm, 3am, 9am, 1pm and 5pm for 30 minutes each time. I know these 30 minute segments wreck the humidity for the bical but are necessary as well. In your opinions how is this in duration and frequency?thx.