Replacing Media in ScaleNet (OneFlow) TAC Units


Media replacement is an easy job on TAC units because only a small amount of media is needed. Residential units use only 2 to 4 liters of TAC media. Be sure you have the right amount of media for your unit before you start. As a rule of thumb, a liter of media treats a service flow of four gallons per minute, so an 8-gpm system would need 2 liters of replacement medium.

  1. Turn the water to the unit off, either with an upstream valve or by putting the red-handled bypass valve into bypass position. (It’s safer to just turn off the water.)
  2. Open a downstream tap to let off pressure.   When no water is coming from the open downstream tap, it’s safe to remove the cap from the tank.
  3. Disconnect the unit using the two black plastic nuts that connect the tank to the bypass valve. If a tool is need, channel-lock pliers, gently applied, are preferred.
  4. Screw the valve off of the tank. It removes counter-clockwise.  It’s like screwing a cap off of a bottle.
  5. On older units, the center pipe (riser tube) stays in the tank.  In new units, the riser tube is inserted into the bottom of the head and comes out with the head when the head is removed from the tank.
  6. When the head has been removed, simply pour the old media out of the tank. It is a good idea to rinse the tank out with a garden hose before replacing the media.
  7. When the tank is empty and clean, pour the new media into the tank and screw the head back onto the tank. In units where the center tube stays in the tank, be careful not to pour media into the tube. Be sure the tank threads are clean and no media is in the threads. It is a good idea to lube the o ring at the bottom of the head lightly with silicone grease. Screw the head snugly onto the tank, hand tight. No tools needed.
  8. Reconnect the head to the house plumbing, then turn on the inlet valve part way and let the system fill with water slowly.  Turn off the water and let the  media soak for half an hour.
  9. Turn on the water and allow water to run slowly through the system and out the open downstream tap for five minutes. It is normal for a few media particles to rinse out of the open tap during startup. After the five minute rinse, check for leaks, and the unit is back in service.