Filter for Graco 1.5 Gallon Cool Mist Humidifier For use in the Graco Cool Mist Humidifier 1.5 Gallon Daily Output. Fits the following: Graco Model 2H00 TrueAir Model 05510 Each easy-to-replace drop-in filter can be changed in about a minute. Replace the filter when it becomes hard to the touch or shows discoloration (which is caused by mineral deposits or mold/mildew buildup).