The recommended filter change period for the Rainshow'r CQ 1000 shower filter system is 25,000 gallons or every 6 - 7 months.
Step One - remove the shower filter from the shower arm by turning counter-clockwise and unscrew the cap from the filter body.
Step Two - take out the used filter cartridge, re-position the rubber "O" rings if they become dislodged. Make sure the O rings and grooves are clean and free of debris that could cause leaks. Dispose of the cartridge or recycle the cartridge by sending to: Good Earth Recyclers, P.O. Box 2167, San Gabriel, CA. 91778-2167.
Step Three - place new filter cartridge into housing body and screw the top back into filter body. Hand tighten only.
Step Four - reconnect filter unit to shower arm by turning in the clockwise direction. Turn water on to allow water to flow through the system for 30 to 60 seconds.