Air moving thru the grow space is beneficial ..whether or not you need a dehumidifier at night depends on the levels you wish to maintain. At 85%, maybe you want to try and lower that but if your fans are replacing the stag air inside, that alone may resolve the problem.
example: An aspirated grow space has a normal influx and exhaust of air and maintains a fairly constant 60% +/- humidity level. For any reason, the power goes out and the circulation of that air ceases to flow. The air INSIDE that grow area will rise in humidity just from the transpiration of the leaves alone and once the circulation and exchange of air is restored, those levels drop to the same level that surrounds the grow space.
this illustration shows the benefits of just exchanging the air inside the room. Simple and other factors will influence the levels but by moving air, you can help to circumvent that issue