9 hours seems like a lot. The spa should filter 4 hours out of a 24 hour time period. If you use it during the day, it will go through a SmartClean filter cycle and automatically filter for an hour. So if you used it for 1/2 hr, that would total 5 1/2 hrs. Are you using it more than that? You can have your bromine level at 1PPM, you might try move the cartridge to a 0 setting. Even on 0 the cartridge still lets some bromine out. Also, are you using the yellow or green cartridge?