hey fugitive... looks like you have that fan blowing into the box? you may want to have it blowing out of the box... if your box is air tight..except for the vents... it will cause suction and it will then only bring in fresh air through your "fresh air tube.." you can guide that air/ direct that air so it blows directly on you plants..

if that tube is coming from OUTSIDE.. you may want to put a fine screen on it or place sticky yellow fly paper paper around... probably both a screen and fly paper.. this will help keep out nasty bugs.. or at least let you know what types of predetors are around

NICE plans!

go get!!!!