Keep in mind if you let the FC go much lower, when you do bump up the CYA your target FC range will slide up a bit as well. I know the app/chart says target for a CYA of 70 is 5, but then you read from the experts here that it's safe to swim all the way up to SLAM level (28) - so currently I've been erring on the side of caution and making my target FC the upper end of the Pool Math range. At least I don't think there is any problem with that...