Metal Ions as a Sanitizer:

Metals such as Silver or Copper can be used as sanitizers and algaecides however they have 2 major drawbacks.  They do not oxidize waste and they stain pool surfaces if not used properly.  Over time, copper and silver salts will accumulate on pool or spa surfaces and form blue or green stains.  Combined with chlorine and sunlight they may form gray or black stains.  Several products are sold to counter this effect, however I have heard mixed response as to their effectiveness.

Since these ions kill bacteria slowly, they usually will not do the sanitizing job by themselves. If you decide to use metal ions you should probably still maintain chlorine at a minimum level of 0.5 PPM.  This level is often recommended by the metal ion salesmen, however NSPI still recommends a minimum level of 1 PPM chlorine for pools and 2 PPM for spas regardless.

The Nature2 cartridge is probably the most popular metal ion product.  It is a container product which is installed inline on the return side of the pump and filter.  Cost is about $80.00 and lasts for 6 months.   The cartridge releases both copper and silver ions as a portion of the pool water passes through it.  The cartridge needs to be "activated" by shocking the pool and running the pump for 4 days.  During this time copper is released into the water.  During the first 2 or 3 weeks copper accumulates in the range between 0.02 and 0.06 PPM.  Silver ions are released slowly over the next 6 months and accumulate in the range between 0.01 and 0.05 PPM  They recommend maintaining 0.5 PPM chlorine along with their product.  I have personally used the Nature2 Express Cartridge and found it to reduce the chlorine demand of my pool, reduce shocking and reduce algae formation.  However, I still maintain 1 PPM so that the chlorine can drift down to 0.5 PPM.

Other products such as 5% Copper Sulfate solutions are sold a primary sanitizers/algaecides.  They contain no silver so it is doubtful that they would do as good a job as a combination copper and silver product.  These products usually recommend maintaining a residual of 1.0 PPM.

Electric Metal Ionizers produce both silver and copper ions by passing an electrical current over silver and copper electrodes in the pool plumbing.  Passing water picks up the ions and dissolves them in the water.  They then combine with bacteria and algae.  Since it may take several hours to bring the ion level up to the recommended level, these products may offer better fine tuning of the copper residual level.  Since these types of ionizers produce both copper and silver ions, they are probably more effective than copper ions alone.

An oxidizer such as chlorine, potassium persulfate or hydrogen peroxide needs to be used to oxidize the waste material.  This is similar to normal shocking which needs to be done anyhow regardless of which primary sanitizer you use.

James Arjuna also known as "The Spa Specialist"  has done extensive testing with metal ions produced from copper/silver ionizers.  Here are some comments I received from him:

"I started using ions after I was told how awful they were by a chemical company representative.   I did severe testing on copper alone, copper and silver, and now copper and zinc.  All of them work just fine.

We have found that the use of copper makes for a much safer ion system than with the Nature 2 or other crystals that have no test kit.  If you  can't test to see if it is in the water, what good is it.

The ions tend to precipitate out of the water at high levels and cause green copper sulfate to show.    I have tried them down two 0.3 ppm and that is when the bacteria will start to grow.    I always recommend keeping them above the 0.3 level.     There are some clarifiers and water treatment chemicals that will remove copper and silver from the water, so we tested and came up with the Vanson , SeaKlear 4 in 1 as a clarifier that works.  The leisure time Spa Defender seems to not affect the ions adversely, but will actually help to hold them in suspension longer.   Can't use any bromine with the copper and silver, it has an adverse reaction and discolors the water.  We use small amounts of chlorine and potassium peroximonosulfate shock to burn out the small organic substances in suspension.

When the silver is used in a swimming pool it can be a bit photo sensitive and "gray" the water a little if it is above 20 PPB (billion) .   I recommend keeping the levels with out unit below .5 in a pool.   There is much less "skin per gallon" in a pool, thus the ions can be less and still be very effective.

I spent a lot of time researching this method and have customers all across the country using it.

If the pH in the water goes above 7.8 the ions will drop down in levels, so the pH is a bit less tolerant with ions."

Jim Arjuna

Jim's Website is



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