kpogue,
well, judging that your tank is 150gal, and mine is 90gal, I'm guesstimating that I'll be topping off close to 1gal every 2 days from evaporation. Which is not too bad.
I will put one fan pushing in, and one pulling out... see how that goes.
I'm going to get 2 220w 5" fans. I'll run them...