Howdy KnowTheGrow, Is Your A/C unit a window unit, or the main central unit for the house? If it is a window unit (a refrigerated unit, not a swamp cooler) try setting it to recirculate instead of exhaust so as to not bring in humid air from the outside. Basically a dehumidifier is an A/C unit, chilling the humid air to condensate the moisture out of the air. Also, make sure that the drain line on the A/C unit is not clogged up and is draining properly (to the outside for the window unit). The central A/C unit should also have a condensate pan and drain line as well, check that as well to make sure that it is draining properly.
Good luck with Your grow.