Gravity feed as illustrated is a great way to go. If lack of space in the stand is an issue and you don't mind a little something set up beside your tank, you could go with a variation of the gravity feed option using a small air pump and a glass wine car boy. This is what I've done since gravity feed is not an option on my sumpless 77. It evaporates close to a gallon a day, so a 7 gallon glass wine carboy lasts me a week. A rubber stopper in the top seals it. The stopper is drilled with two holes through which two rigid air lines are pushed. Flexible tubing connects an air pump on a timer to the car boy. The pump runs a few minutes every hour or so and pressurizes the carboy. More flexible tubing transports the water to a mechanical furnace humidifier float valve attached to the rim of the display with a diy acrylic bracket. Nice steady trickle keeps things stable. Only real downside I can think of is the carboy sitting there on its stand next to the display. Things I like, simple with no electrical gizmos (i.e. float switches & pumps) in direct contact with the water.
