I am having trouble figuring out how to get the water sensor in properly. If I put it in the way(down) that the picture seems to show it is resting against the top of the pump. If I put it in so the sensor is up it does not look as if there is a difference between the light sensor and the bottom of the back up sensor. Also where does the blue foam filter pad go. A picture of the inside of the unit set up correctly would be usefull. Thank you for your help.