Silver is used as a powerful
bactericide in many products, and copper is used as a common
algaecide. As water contacts these minerals, positively charged
ions are released; these destroy negatively charged contaminants.
And that makes these particular minerals well-suited for use as
supplemental sanitizers in residential swimming pools and portable
Ions at work
Silver and copper are most effective in water in their ionic form.
That means the molecules are independent from other compounds and
carry a positive charge. These charged ions are attracted to
negatively charged organics such as bacteria and algae. Once
attached, these ionic elements destroy the organics by penetrating
their cell walls.
Because the ions are unaffected by sunlight or heat, they can
remain active in water for long periods. They are only removed by
reacting with the organics or from splash-out. There must be a
constant flow of these charged ions introduced to the water in
order for this process to be effective.
Active and passive ionization
There are two types of devices manufactured today that accomplish
this process — one using an active method and the other using
a passive method.
Active-method devices create ionic silver and copper by applying a
low-level direct current to electrodes that are plumbed into the
filtration system. The electrodes, which are made from combinations
of silver, copper and sometimes zinc, quickly release their ions
into the water as they erode from electrolysis. The electrodes must
be replaced periodically, and the water must be tested regularly to
ensure the silver and copper levels do not rise to a point where
staining could occur.
Sequestering agents are recommended with this method to prevent any
possibility of staining. These devices were common in the 1980s and
‘90s, but they never reached mainstream status as sanitizers.
Most pool professionals feel they were oversold as a total
replacement to chlorine, or were installed and used improperly.
Recent technology seems to take into account the lessons learned
from the past, but ionizers are not what most people think of when
mineral sanitizers are discussed.
Passive-method devices are usually what come to mind when
discussing mineral sanitizers. They do not use any electricity,
instead utilizing a flow-through cartridge containing a substrate
that is coated with silver or impregnated with a combination of
silver and copper. The substrate is made of small pebble-sized
pieces that are retained in the plastic cartridge. The cartridge is
then installed in a vessel that is plumbed into the pool’s
filtration system. As the water passes over the substrate, silver
ions or a combination of silver and copper ions are slowly
Sequestering agents are not necessary, since the ions are released
so slowly. The cartridge contents will remain active for up to 6
months in pools and 4 months in portable spas. Passive devices are
also a perfect complement to salt-water chlorinators. They do not
interfere with chlorine generation, and many users find that they
can turn the chlorine production rate down, making the electrolytic
cell last longer. Passive devices are a preferred method of using
copper and silver vs. adding them via a powder or liquid form,
because those products usually are mixed with chemicals.
The U.S. Environmental Protection Agency (EPA) plays an important
role in the regulation of mineral sanitizers. While the copper and
silver elements are considered safe, when an efficacy claim is made
regarding algae or bacteria control, the EPA regulates its use.
Therefore, make sure the product you use has an EPA registration
number, lists the active ingredients, and shows all the cautions
that the EPA requires. Though the EPA regulates and verifies the
claims of mineral sanitizers, they do not regulate the
product’s potential to stain or cause other problems. Look
for products that are guaranteed to work and guaranteed not to
stain the pool.
Benefits of mineral sanitizers
Neither the active nor passive methods eliminate the need for
chlorine in a swimming pool, because minerals lack the ability to
oxidize dead contaminants. Fortunately, the two biggest benefits of
using minerals are a reduction in the amount of chlorine needed to
maintain a residual, and the ability to maintain a lower residual.
With a mineral sanitizer, you will notice at least some of the
- No more algae
- Fewer complaints about skin and eye irritations
- Fewer shock treatments required
- Fewer pH adjustments needed
- The TDS reading does not increase as quickly
The best testimonials for mineral sanitizers come from the pool
professionals who use them. They report many benefits, such as
getting rid of problem algae spots, lowering chlorine use, more
consistent chlorine readings, and pools that stay sparkling clear
with less work.