It isn't hard wired, the pump connects to a European connector, it is connected by screw terminals essentially. You replace the pump with the switched socket 3150.110. Then the same DC signal just switches a relay and turns on a 115V socket.
If you need less flow the simple solution is to install a drip irrigation valve at the end of the top off hose to restrict the flow. The switched socket only comes into play when you need more flow for huge tanks.
After 10 minutes it must be manually reset, the logic is that if it takes more than 10 minutes your tank or plumbing is probably leaking and more water is just adding gasoline to the fire. In 10 minutes it will pump 2-3 gallons, it is so sensitive that it activates with less than a 1/8" water drop so a system would need to be huge for 2-3 gallons to be the required top off, usually it is dispensing on the order of a few tablespoons or a cup of water at most. It does not self reset, only a power interruption can reset it.
The optic sensor turns the pump on as needed, this will depend on evaporation rate. It waits until the water is below the sensor for about 8 seconds to accomodate for waves or disturbances. It overfills as well for about 12 seconds to reduce how often it cycles on. On a small tank, 12 seconds can be enough to trip the safety alarm so that is where the drip valve would come into play.
Switching it would eliminate the 10 minute safety, you reset this everytime you switch. If you just use it as is it has an optic sensor, 10 minute time out and safety float switch. If you install it properly so it cannot siphon and you use a reservoir of a volume that is just sufficient for 1-2 weeks of top off, you can be certain it is very safe and there is nothing you could do to make it better. We pretty much thought of everything.
