cheese auto

QUESTION-------- I have a small grow tent 2x4x5tall. I have a really good exhaust fan venting to the outside (150cfm). I have a small stationary "clip" fan..... the air coming from the room into the tent is about 45-50rh. I CANNOT seem to get my rh inside the tent any lower than 65%rh!!! I'm thinking my choices are to buy an intake fan and try to Port some air in, OR buy a better small ocsillating fan. I am in need of some advise as I can't fit a dehumidifier in the tent. (sidenote, I've also seen discussion of a "dump fan" setup, would that solve the issue?) no big buds yet. hope they are coming soon!