True, true if the waterfall and the siphon tube are in close proximity but in this case the water fall will go into a small pool then via a short creek to the main pool that will be under all the landforms and never near the incoming water.

Also with the pump in the tank if anything went wrong (and it will) I'd have to do a major demolition to get to it not to mention the extra space all the plumbing would take up. There's just too little space in a 12in wide tank.

In either case there is the need to constantly monitor the water level.

Robert

Never heard of an auto topoff unit, have you? It's a fairly simple way of maintaining a cconstant water level.

A great idea and yes I''ve thought of it but the terrarium is in the dining area no where near a water source so, unfortunately that possibility is out.

Robert

No room for a container under the tank?

Unfortunately no. The cabinet is the only flat spot in the house suitable for the tank and it is full of dishes and bowles.

Robert

Since your "sump" is really nothing more than a cooling bath for your pump, why not use it?

My friend, you can try an windshield pump under volted, let say 8V, if vork, works, if not is not too expensive and can be used for misting

I considered this but siphoning would mean sucking all the water from the tank thus emptying it and pumping all the water from the sump back into the tank, a truly open system and a sure method for burning out the pump.

Certainly something to consider since I will want a misting system.

It's much easier to maintain a steady water level in a larger container. If the level in your pool in the main tank drops too low it will burn the pump out just as surely.

Granted and that is why constantly monitoring the water level is necessary. The water level in my tank will, hopefully, be not more than 2 to 2-1/2 inches. We'll see how that works out.