Turn off the water to the unit by the bypass valve.
Unplug the unit from the electric source.
Disconnect the unit from your plumbing.
Carefully unscrew the control valve off the top of the tank.
Inside of your tank is plastic tubing known as the "riser tube". The riser tube sucks up the water from the bottom of the tank during normal operation, and forces water to the bottom of the tank during the backwash operation. After removing the control valve from the tank, remove the riser tube from inside the mineral tank.
Lay the tank on its side, or lay over trash can, to remove media.
Rinse the inside of the tank clean with a garden hose.
Discard old resin.
Save old gravel.
Make sure your media tank is standing straight up.
Put a piece of tape over the top of the riser tube to prevent media from entering the tube while you are loading the media.
Put the media funnel included with your system in the top of the media tank with the riser tube still inside and centered.
The gravel goes into the tank first. When pouring in the gravel, make sure the riser tube is firmly on the bottom of the tank. Once you add your media, if the riser tube is pulled out of the gravel, it is impossible to put it back in without removing the other media from the tank.
Pour the resin/media into the funnel, slowly letting it fall down inside the media tank around the riser tube. If you have a twin alternating system, divide the resin/media equally between the two tanks.
When you have poured all of the resin/media into the media tank, it should be approximately 3/4 full.
Remove the funnel and then the tape from the top of the riser tube.
Brush any loose resin/media off the top opening of the tank. Clean the top edge with a cloth so the O-ring can seal securely to the valve base.
Look at the bottom of your control valve and you will see an upper basket Inside of the basket, the control valve has O-rings that will seal on the riser tube. Tilt the valve over on top of the media tank making sure the top of the riser tube inserts inside the opening of the upper basket. Guide the riser into the O-ring seal and tighten gently. Be careful not to over-torque the valve as the threads are plastic.
Screw the control valve back onto the top of the tank. Be sure to hold the control valve where there will be no damage to the valve from the pressure you exert from tightening the valve back onto the tank.
Reconnect your plumbing to your unit and plug it back in making sure to set the correct time of day. Turn the water to the unit on and check for leaks.
Leave all faucets turned off inside the house, and open a single faucet (such as an outside faucet) letting the water run for 3-5 minutes. This rinses the new resin/media off inside the tank, and any particles or color will rinse out through the one open faucet, and not throughout your home plumbing system.
Manually turn your regeneration/backwash control knob slowly through a complete cycle, allowing the water to run through the unit in each position for a minute or so.
Once the regeneration/backwash knob is back in the service position, your unit is back to service and ready to operate!