Question about optical sensor and leakage detection

[doggydoc10]

Well here is my ordeal. I have my main return pump connected to an optical level sensor in my overflow box set up as leakage detection to avoid leakages via the overflow.
Here is the problem: I had a power outage this am that lasted approx 2 hours. Water raised in the overflow to a level that covered the sensor. Since sensor is connected to pump, when power came back, sensor was under water so pump DID not turn on.
Is there anyway to go around this?
Inquiring minds want to know!!!!

[Matthias]

So you want to switch off the return pump when the sump is too full? Does this make sense at all?