For those of you who have the Acu-Rite digital thermometer/hydrometer with probe, can you tell me at what humidity it would just read "HI"???? I think it is 90 or above, but I can't find my manual, so I'm not sure. If that is the case, then no wonder I've had to keep my humidity so high to get a good hatch. I think I'm going to go buy a new one, since is seems rediculous to try and use a hydrometer that reads more than 15% too high! I'm so glad I finally calibrated it! I will bring it with me when I go to Wal-mart, and make sure I don't choose any that have the same reading as mine!