ATO reservoir Level

[lbs5015]

I'm pretty close to pulling the trigger on a Profilux 4, this will be my first aquarium controller. Currently I use a Tunze ATO, with the pump in the ATO reservoir. I'd like put a low water level sensor(float or optical?) in the ATO reservoir and have the P4 email/Alert me when the reservoir is low so I know to refill it. I don't need it to turn off any pumps or sockets or anything yet (will eventually have the P4 control all ATO operation and reservoir level). I'm sure the P4 is capable of this but just wanted to verify that this is possible and which type of sensor is better to use for this purpose and would I program the sensor for leak detection? Thanks.