I have a ceramic tile substrate with a layer of sand underneath. The ceramic tile is a pretty tight fit but I am sure that over time, urine and other debris may get through the cracks and get to the sand underneath. So my first question is, does the sand ever have to be replaced? If so, how often? My next question is cleaning, as I am a brand new leo owner. What do you use to Spot clean? Every morning so far, I've just been cleaning up his business with a paper towel and wiping down the area with warm water. What does everyone else use for spot cleaning? Soap? products? Or is what I am doing fine?