Dennis, I think you should go with the 40 breeder. I have a 30 that seems not quite deep enough for a really nice aquascape. The weight difference of the two tanks should not be an issue on a second floor. Moving a tank is always a hassle so that wont matter between the two.The extra 6 inches of depth should sway you to the bigger tank. I will try to get some pictures of my 30 posted. You will surely recognize most of the plants.