Ionizers

Ionizers produce metal ions in the plumbing of a swimming pool through the use of electricity and are then passed into the pool water to sanitize the water by killing bacteria and algae.
 
Depending on the ionizer, the equipment sub panel uses a low-voltage DC current to energize silver and/or copper electrodes.  Silver is known to kill bacteria and copper inhibits the growth of algae.  The electric current created by the low voltage introduced to the metallic electrodes within the plumbing causes the silver and/or copper electrodes to lose atoms to the passing water.  These ions then float around in the water until they encounter bacteria and/or algae.  Ionizers can reduce some of the dependence on chemicals, or can work in addition to a pool sanitization routine, but should not be used alone without chlorine, bromine or some other type of basic pool sanitizing chemical.  Ionizers may also cause some staining to the interior of the pool.  Silver might cause a black stain, while copper may cause a blue-green stain.