Soldato
Mine looked near identical to this:
https://www.youtube.com/watch?v=7DFk4bnIxEg
Worked perfectly, and no way it can overflow/flood the room. Even if the entry got blocked, it would just cease when the waterlevel in the sump got too low (pump with auto cut-off), and even if it didnt stop the pump would not pump water once the level was too low. I just had a 90 degree on the inlet, and some mesh in front of it.
It was failsafe, cheap, and easy to do.
So in the way you set it up, there isn't enough water in the whole system to overflow the main display. There's just enough water to create the syphon, and the pump in the sump is only slightly submerged, so if there's a blockage the system shuts down quite quickly. Is that correct?