If you have a large, open top aquarium that sits inside your home, then chances are that elevated humidity levels are a constant battle. Metal objects rust, rooms are hot and musty, and the tank is making things unbearable. You could always crack a window, but this isn’t a go-to choice every time. And nobody wants to run their air conditioner all of the time. What you could do, instead, is run a dehumidifier. The dehumidifier will remove some of the moisture from the air, possibly making the aquarium room a bit more bearable. Keep in mind that using a dehumidifier might increase the evaporation rate of your aquarium water, as the air is a little drier. On the plus side, your tank should run a little cooler, though it may not be noticeable.