Use multiple temperature sensors on your system for safety and redundancy. Place one in your fish tank and another in your sump. This can help if your tank is in a headhouse while your plants are in another room.
Configure the HYDROS app to set safe temperature ranges so that if the water temperature drops or rises out of the safe range, you receive a mobile alert. You can also set it up so that outlets with a heater, chiller, or fan plugged into them turn off when the temperature is outside the safe zone.
This sensor must be plugged into a HYDROS Controller for this sort of automation to occur. HYDROS Controller NOT included.