A water softener turns hard water, which is water with more minerals and hasn't been filtered, into soft water, which is water that has been filtered and has a lot less minerals in it, and the resin tank is where all the minerals taken from the hard water comes from. If a resin tank cracks or has any other kind of holes in it, the minerals previously in the water will flow through the crack and mix in with the clean water or soft water.
Step 1 - Cutting off the water line
Cut off the main waterline near the pressure tank. Open a close conditioned water faucet to vent pressure away from the unit. Finally, unplug the transformer from electrical power as to not injure yourself or anyone else.
Step 2 - Open the water softener
Push the bypass valve stem in for bypass. Remove the salt cover and set aside so it won't be in your way. Slide the top cover forwards to expose the inner valve. Carefully disconnect the the wiring harness from positioning switch. Slowly and safely unplug the motor terminal from the back of the electrical control board. Then set the top to the side out of the way.
Step 3 - Separate the resin tank from the softener
Carefully remove the retainer clips from the softener inlet and outlet. Also separate the water softener from the bypass valve. Use needle nose pliers and lift the drain clip to expose the valve drain hose adapter and remove it. Disconnect the brine line from the venture assembly ad nozzle by losing the ferrule nut. Remove valve from the resin tank and set it out of the way. Remove the vapor barrier and locking plate to remove the tank. Slowly and carefully take the resin tank out of the salt storage tank and replace it with a new one. Remove the shipping caps by taking the clips and clamp sections around the tank neck.
Step 4 - Putting everything back
When the tank is where it should be, replace the vapor barrier and locking plate back into the salt storage tank very carefully. Be sure that all parts that you put back into the softener is clean of resin and other material especially the bottom of the valve assembly. Lubricate the o-ring sealing surface with grease at the bottom of the valve. Locate the distributor o-ring and do not lower it on top of the distributor. Slowly lower the valve assembly onto the tank and align it with the riser pipe while working it over the o ring and onto the adapter make sure to then clamp it in place. Carefully reconnect the water softener inlet valve and outlet back together with the bypass valve. Reconnect the bring line to the nozzle and venture assembly by hand tightening the ferrule nut. Reconnect the valve adapter to the valve and then connect the motor terminals to the electrical board. Test to see for a constant flow. Slowly move the bypass valve stem to allow the unit to pressurize.