I am gonna try the top and see if that helps with the evap. its more because thats a 20 dollar fix instead of a 120 dollar fix and it will keep me from loosing fish or the dog trying to drink out of the tank (I caught him this morning) Also with the heat if i need to I can always unplug the heater during the day while the lights are on and then plug it in at night. Since there aren't any fish in it currently i feel a little more comfortable playing with the tank I dont want to place fish in the tank until I know i've got everything pretty stable.