Do you use insulted duct on your cool tube? Do you have to have your chiller and or res in the same room? You could also look into a sulfur burner--will take care of all powdery mildew l all mold except for deep bud rot-and you run a risk of that with your humidity at 70. I have a 10,000 btu delonghi that works like a charm in a flowering room--no drip pan and humanity goes out with exhaust the unit run 110v--8.5 amps on full---1050 watts.(problem is that it sucks out your co2 and smell)---I run tanks in the summer and have a natural gas burner for the winter. My light system is passive with insulated ducts and sealed reflectors. I only run my exhaust at night when the light are off.