We upgraded to a Summer Waves 16x42 elite pool this year. I already have a Intex Sand filter and want to go from the SFX Filter to the Sand filter. I have the adaptors and everything that is needed to convert. I have already filled the pool, because i figured it would take a lot longer to figure out how to convert.. The Summer Waves pool comes with a water stop that supposed to prevent the water from flowing into the skimmer while trouble shooting. For the life of me I can't get the water stopper to stay in place for more than 2 seconds. I'm trying to prevent a lose of water. Any suggestions on how to get the water stopper to work?