We had a short power break this morning and my sump started to overflow into the living room. I am very glad that I was home when it happened.
After cleaning it up I went to check what caused it. I turned off the pump and watched.....the water from the overflow stopped but the water level in the sump kept rising...and rising...and rising. The only thing that it could be is that the line for the pump is causing a reverse syphon when there is a power failure.
I'm going to home depot after work today to get some solid PVC
tubing. I've attached a drawing of what I am hoping to do. By having two holes near the top of the water surface, this should break any syphon that was created, no? As the water drains back towards the sump the level will lower, expose the hole and break the syphon.