How Water Softeners Work

Modern water softeners use a system containing ion exchange resin to remove hardness minerals from hard water. This process eliminates scale buildup in hot water systems, bathrooms, and shower fittings, and prevents scum from forming when soap is used.

1. The resin tank: Contains the ion exchange resin.

2. The brine tank: Holds salt that dissolves into brine.

3. The control head: Determines when regeneration occurs and manages valve operations during regeneration.

In most modern units, the resin tank is located inside the brine tank, which forms the external cabinet of the softener. These units are typically compact enough to be installed conveniently under a kitchen sink.

These are the most common type and use one resin tank. For regeneration, the tank must be taken out of service, and a bypass valve opened. This means only hard water is available during regeneration (which can take 12-90 minutes), so it's usually programmed for nighttime.

Many softeners operate on a time control basis, which is typically the simpler and less expensive option. The timer calculates the regeneration frequency based on factors like the number of days the system will operate, household size, softener capacity, and water hardness. Regeneration is then set to occur at a specific time nightly. These systems regenerate at preset intervals regardless of actual water usage. It's advisable to switch off the softener if it won't be used for a period, such as during holidays.

These systems aim to adjust to demand and avoid over or under-regeneration, initiating regeneration once a preset volume of water is used. While theoretically efficient, this can be inefficient for small softeners because the preset volume (which can be 30-50% of the softener's total capacity) might be reached at any time during the day, leading to frequent regeneration and under-utilization of capacity.

More sophisticated systems monitor daily water usage to ensure regeneration happens on the most opportune night, guaranteeing continuous soft water availability. They also adjust the amount of salt used during regeneration to match actual water consumption, reducing waste. This method is ideal for small single-cylinder water softeners as it efficiently restores resin capacity and optimizes salt and water usage.

These systems use two resin tanks, with one in service and the other on standby. Some systems use both tanks simultaneously but require partial shutdowns for regeneration. The control system monitors water flow, switching to the second tank once the first is exhausted, then regenerates the first tank while the second is in use. This ensures a constant supply of soft water, even during regeneration, with the system continuously swapping tanks as needed.

Twin tank systems regenerate based on volume, utilizing the resin's full capacity for each service cycle. While adapted for small domestic systems, their very small resin tanks can limit flow and result in a high percentage of total water being used during frequent, small regeneration cycles, leading to wasted water. Additionally, small twin tank softeners use a lot of salt to maximize capacity between regenerations.

Some twin tank brands feature non-electric control heads that use water pressure to operate valves and measure flow. These are commonly found in small domestic water softeners and share the same limitations as other small twin tank softeners, including higher wastewater volume and limited flow.

There's a wide variety of brands, sizes, and cabinet designs available. All systems use the proven ion-exchange process but differ in their operational and control technology.

A water softener typically has a lifespan of 10 to 20 years and can be moved if you relocate. To choose the best model for your needs, I recommend scheduling a free telephone consultation at 0800 068 1857.

Our specialists can discuss the pros and cons of various models, and recommend the most suitable product for your requirements, household size, and budget.

We will, of course, need to visit your home to survey for installation.

Contact Us today for a friendly advice!