Suggestions for a pump cutoff trigger

Greetings everyone.

I’m looking for a simple way to trigger a water pump to switch off once a tank has reached its fill level.

I have been using one of these leak sensors which sends a 433mhz signal to a Sonoff bridge which in turn switches off the sonoff POW switch which is connected to the pump.

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This works perfectly except for the fact that the leak sensors remain underwater for a few hours until the water level in the tank starts to drop. During this time the sensor keeps sending the 433mhz signal until it’s battery dies. This means it only lasts a day or two before the battery needs to be replaced.

So I need to come up with another plan. I was thinking of using a float switch like this as the detection mechanism, but I’m not sure what to connect it to.

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Preferably something that can send out a single 433mhz inching signal and then stop.

Any suggestions?

Thanks very much.