Hi ! I'm curently building a darkroom in my basement. The darkroom will be 2.8 m x 3.8 m and about 2 m high, this goes to a total of 20 cubic meters for the volume. What would you think is safe for a replacement rate ? I do not want to have to attach the enlarger to the walls to resist the blow ;-) (it is not particulary light, as it is a Durst Laborator 1000) My setting will be : succion above the sink and inlet of filtered air near the enlarger, flow coming in will be more powerfull than the exhaust (to put a positive pressure to resist dust coming in) TIA !