I have a problem with my spillover spa - there is a stone spillway the water is supposed to flow over, but instead is flowing under and down into the wall. It’s pretty clear that some type of sealant (silicone?) was preventing this and has peeled away in sections - does anyone know what this is and any tips for repairing it? Or what would be good for sealing the gap between the liner and the stone? My pb has proved pretty useless in helping me, so hoping to do it myself.