What is the make/model of your humidifier, and the size of the room? Also how many plants do you have and do you have any other source of water vapor in the room, like an aquarium? Oh, and do you live in the tropics? Just curious because I have major humidity issues too, purely because I live in a northern state, have my house sealed up tight during the winter, and live in a small space, with a dog, and two turtles, and several very thirsty plants. My 30 pint dehumidifier runs 24/7, I empty about 4 gallons per day and it keeps my RH just a hair under 50%, so, pretty perfect. But as you can see, I have a TON of water in my air if not for the dehumidifier. I'm curious how much water yours removes? I agree 100% about air flow, be sure you have a lot of air flow above and below the canopy, be sure to defoliate the dense undergrowth that is not exposed to light. I'd also get a good biofungicide and treat them asap, like Southern Ag Garden Friendly Fungicide, or if you have the cash, Regalia. Another cheap thing you can do is give them a dose of aspirin water, 1 325mg tablet per gallon, dissolved well. It's also good to apply the aspirin water as a foliar-lots of studies on this if interested.
