Nightly Exhaust Cycle

Ok I'm doing a DWC hydro grow and I have some monsters on my hand and I've noticed that at night moisture builds up on the leaves of the plant so I added and exhaust time to vent out for 10 minutes every two hours. Is this a common problems for people and if so how do you run your exhausts cycle this is a new grow room and I haven't experienced this b4. I know we love pics so here's one just for you all.

Wow nice plants, looks like a jungle in there. I don't know about moisture build up and I don't want to come across as a nit pick, but the electrical strip should be above the water-line. Thems gonna be MONSTERS