We have an in-ground spa. We had a leak and the pump ran overnight and pumped all the water into the yard. Because the water was in the yard and not the spa, the spa floated up out of the ground. We would like to install a pump shut-off when the water level drops below the skimmer box. This was a very costly and annoying issue. Please tell me how we can add a switch to shut down the pump if this happens again. We have asked pool and spa companies and they have no answers.