DKoKoMan's 150g Reef Tank

[DKoKoMan]

So I have run in to some issues with humidity in or basement. I have found that the floor has been sweaty now that the weather has warmed up (25-26 Celsius). The walls and windows show no humidity whatsoever.

My wife says it feels damp and humid in the basement. I notice it more now that I have the larger tank as compared to my 75g. I currently have the top of my aquarium covered with a plastic grate to still allow for air exchange.

Has anyone had similar issues? I am thinking of getting some plexi glass pieces made for the top to reduce evaporation. Will this work or is it not worth it? Also is this going to effect the gas exchange?

I picked up a 70pint dehumidifier yesterday from Canadian Tire. Within hours the basement felt much drier and no more moisture on the floor. My fear is that this will suck water from the tank?

Any help would be appreciated.