Water Softening resin cartridges only have a small volume of resin and therefore need to be changed or regenerated regularly. Once regenerated the capacity will not be the same as a new cartridge with virgin resin. Regenerated resin has 20-30% lower capacity than virgin resin but can be regenerated over and over for many years (10-15 years) as long as it does not get contaminated with organic matter such as clay, silt etc or iron.
Regeneration is an easy, inexpensive process that takes on a few minutes and saves replacing the cartridge every few hundred litres.
1. Reverse the flow/ back flush clean water through the resin cartridge to remove the calcium, magnesium and as many other contaminants as possible. This should be done for 5 minutes with a high flow rate if possible. Once complete remove the cartridge from the housing and drain as much water out as you can.
2. Buy a bag of standard table salt. Iodised is okay but plain is best. Place 3 cups of salt in a 5 litre jug, plastic container or stainless steel pot. Add 3 litres of water and mix to dissolve salt. It does not matter if it does not all dissolve as the water will reach a saturation point where no more will dissolve. This point is generally around 350 grams of salt per litre of water.
3. Place the resin cartridge in the container of salty water making sure it is covered. Let it sit for at least 30 minutes to an hour or overnight if possible. The salty water or brine solution will dislodge the calcium and magnesium ions on the resin replacing them with sodium or salt. This regenerates the resin ready for re-use.
4. Place the cartridge back in the housing and run water through it to drain for a couple of minutes to rinse out the excess salty or brine water. It is now ready for use and must be kept moist or wet. If it dries out, the resin will need to be replaced.
You might consider buying a spare cartridge or two so that one can be recharged while another is in use.