If memory serves, the instructions on the Spa Frog say to open the bromine cartridge wide open for 24 hours (to establish your bromine bank), then set it back to #1 after that. My dealer's instructions say to set it wide open for 8 hours, then check bromine level and then set to #2. I followed the dealer's instructions on my first fill, but found that the bromine got too high after awhile, so I set it back to #1. Bromine has been between 1 and 3 PPM ever since.
YRMV, depending on how you use your tub and maintain your water.
