Cheap Water Softener Salt: Why Is It So Cheap? - Friendly Water

Cheap Water Softener Salt: Why Is Cheap Salt So Cheap?

As with most things in life, a lower price usually means lower quality. But does that really matter when it comes to water softener salt? After all, it’s just salt… right?

Well, no.

Poor-quality water softener salt can cause serious problems. When salt tablets break down inside the brine tank, they release contaminants into the system. This can lead to blockages, reduced performance, and in many cases, expensive repairs.

Bad Quality Water Softener Salt

The image below shows the inside of a water softener salt tank filled with tablet salt that has failed. The tablets have disintegrated, contaminating the system and ultimately resulting in a costly repair that could have been avoided with better-quality salt.

Good Quality Water Softener Salt

The second image highlights the visible difference between salt from different sources — even when brand new and straight from the bag.

The beige salt on the left is solar-evaporated sea salt, manufactured in the Middle East.
The white salt on the right is produced in Northern Europe using Pure Dried Vacuum (PDV) methods and manufactured to BS 998 / EN973 Type A standards.

The difference in purity, consistency, and performance is clear.

What Makes a Good Quality Water Softener Salt: Tablet Salt or Block Salt?

The most important factor is the raw material (feedstock). Tablet and block salt can be produced from various sources, each with different purity levels and contamination risks.

Common Salt Sources and Quality Levels

Rock Salt – No recognised standards
Likely contaminants: mud, stones, gravel.

Sea Salt – No recognised standards
Likely contaminants: sand, organic remains, debris.

Solar Salt – No recognised standards
Likely contaminants: sand, minerals, organic material.

Food Grade Salt
According to International Codex standards, food grade salt must contain at least 97% sodium chloride (NaCl) but may come from any of the above sources.

“Food grade salt is a crystalline product consisting predominantly of sodium chloride. It is obtained from the sea, underground rock salt deposits, or natural brine. The NaCl content shall not be less than 97% on a dry matter basis, exclusive of additives.”

Pure Dried Vacuum (PDV) Salt – BS 998:1990 / EN973 Type A

PDV salt is widely accepted as the highest quality feedstock for water softeners. It requires a minimum of 99.6% NaCl and must meet strict limits for impurities and contaminants.

Although PDV salt costs more, it delivers cleaner operation, better reliability, and long-term protection for your water softener.

Be cautious of salt labelled only as “Food Grade” — a 97% purity level allows up to 750 grams of impurities in a 25kg bag.

Manufacturing Factors That Affect Water Softener Salt Quality

In addition to raw material purity, the manufacturing process plays a crucial role in tablet and block performance.

Particle Size Distribution

This determines how strong the finished tablet or block is and how resistant it is to breakdown and efflorescence (salt creep).

Compaction Pressure

Higher compaction creates stronger tablets that break less during transport and produce fewer fines. Lower pressure uses less energy and results in cheaper — but weaker — products.

Moisture Content

Some low-cost tablets are made from undried salt, meaning part of the pack weight is water, not salt. Higher moisture content also causes tablets to disintegrate more easily.

Salt Creep (Efflorescence) and Salt Bridging

Poor-quality salt absorbs more brine when standing in the tank. As the water evaporates, fluffy crystals form around the edges of the tablet or block. These particles interlock, causing tablets or blocks to fuse together into a solid mass.

This leads to salt bridging, where the softener appears full of salt but no salt is dissolving. Salt bridging is a major cause of softener failure, results in hundreds of service call-outs each year, and is not covered by manufacturer warranties.