it should be noted that in the detailed description which follows , identical components have the same reference numeral , regardless of whether they are shown in different embodiments of the present invention . it should also be noted that , in order to clearly and concisely disclose the present invention , the drawings may not necessarily be to scale and certain features of the invention may be shown in somewhat schematic form . with reference to the drawing figures , a water ionizer 10 according to the present invention is shown to generally include an enclosure 12 to which is secured an electrode housing 14 . the enclosure 12 receives and surrounds a series of electrical components that control and indicate operation of the ionizer , as will be discussed more fully hereinafter . the enclosure 12 is preferably provided by a first piece 16 and a second piece 18 . the first piece 16 is l - shaped in cross - section and provides front and top walls 20 , 22 of the enclosure . the inner surface of the front wall 20 has one or more circuit boards ( not shown ) and a piezo - electric vibration sensor 23 secured thereto . the piezo - electric sensor 23 is preferably adhered to the front wall by a suitable adhesive , such as a pressure sensitive adhesive . one such sensor which has been successfully used by the applicant is manufactured by amp and sold as the ldt series element ( ldt 0 - 028k / l ), part number 1002794 - 2 . the front wall 20 also has an opening therein through which a temperature display ( not shown ) is visible . the front and top walls 20 , 22 include a peripheral flange 24 to which the enclosure second piece 18 is secured by means of sheet metal screws . the enclosure second piece 18 defines rear , bottom and lateral side walls 26 , 28 , 30 of the enclosure 12 , and generally overlies the circuit boards . as such , the first and second pieces 16 , 18 cooperate to define a space in which the electronics are received . the front wall 20 extends downwardly below the bottom wall 28 , and conceals the electrode housing 14 . the bottom wall 28 includes a series of openings into which electrode housing mounting screws are threadably received . accordingly , the electrode housing 14 is generally disposed beneath the bottom wall 28 and behind the front wall 20 and , as such , is protected from damage . the lateral side wall 30 has an indicator circuit board ( not shown ) secured to an inner surface thereof . the indicator circuit board has a plurality of light - emitting diodes or lamps that are visible through a like number of openings 32 in the side wall 30 . the lights or leds are illuminated to indicate operation of the ionizer ( i . e ., power on / off ; service required ; bar 1 ; bar 2 ), as will be apparent from the discussion to follow . the indicator circuit board also has rotary adjustment shaft 33 extending therefrom . the shaft 33 projects through the sidewall 30 and permits the user to adjust the operation of the ionizer , as will be described hereafter . the rear wall 26 has a transformer secured thereto which provides power , at a reduced voltage , to the circuit board . the bottom wall 28 has an opening through which a power cord 36 extends , an electrode lead wire opening through which an electrode lead wire 40 extends , and a sensor opening through which a temperature sensor ( not shown ) extends into a well 38 provided by the electrode housing 14 . the power cord 36 supplies household power to the transformer . the electrode lead wire 40 extends from the front circuit board to electrode terminals 41 on the electrode housing 14 . the electrode housing 14 defines a portion of the water flow path between a pool filter / pump ( not shown ) and a pool ( not shown ). more specifically , the electrode housing 14 has a cylindrical body 42 to which a mounting bracket 44 is secured and from which a cylindrical projection 46 extends . the mounting bracket 44 provides a generally planar outer or upper surface which abuts an outer or exterior surface of the enclosure bottom wall 28 . the mounting bracket 44 has an opening formed therein through which the temperature sensor well 38 is accessible . the temperature sensor well 38 extends into the hollow interior of the body 42 and permits a temperature sensor inserted in the well 38 to monitor temperature of water flowing within the electrode housing 14 . the cylindrical projection 46 is generally on an opposite side of the body 42 from the mounting bracket 44 , and extends away from the mounting bracket 44 . as such , the electrode housing 14 is t - shaped , with one arm of the &# 34 ; t &# 34 ; being longer than the other , as illustrated best in fig3 . the cylindrical projection 46 is adapted to receive a cap 50 comprising a pair of electrodes 48 . in the preferred and illustrated embodiment , the cap 50 is sealingly secured within the cylindrical projection 46 . the electrodes 48 extend or project into the hollow interior of the body 42 . each of the electrodes 48 is connected to power via the associated electrode terminal 41 extending from the cap 50 and lead wire 40 . the electrodes 48 are supplied with power in an alternating fashion to ensure that the electrodes wear or erode at a uniform or even rate . the supply of power is regulated by the front control board such that the polarity of the electrodes is switched periodically , such as every 30 seconds of operation . the lamps or led &# 39 ; s are illuminated corresponding to the operation of the water ionizer . one lamp is illuminated when the ionizer is turned on . a second lamp is illuminated when one of the electrodes is supplied with current , and a third lamp is illuminated when electrode 48 polarity is switched to supply the other one of the electrodes 48 with current . the fourth lamp is illuminated when the ionizer requires service . the &# 34 ; service required &# 34 ; lamp will illuminate when conditions are indicative of the electrodes 48 being worn or eroded to the point of not being further useful . typically , the &# 34 ; service required &# 34 ; light is illuminated when , during otherwise normal operation of the ionizer , the current between the electrodes 48 falls below a predetermined minimum level . this may occur when power is no longer supplied to the electrodes 48 due to a loose connection , or when the electrodes are eroded . when the ionizer is initially powered - up , the &# 34 ; service required &# 34 ; light may be illuminated due to the low level of total dissolved solids . it is important to build up a copper residual from an initial zero level to an operating level of between about 0 . 3 - 0 . 5 ppm . accordingly , the control knob is turned to the full - on or maximum position to quickly build up the copper residual to an operating level between 0 . 3 - 0 . 5 ppm . however , copper residual is not easily built - up when the total dissolved solids is less than 1000 ppm . the total dissolved solids can be quickly increased by adding salt to the pool water , thereby permitting the establishment of a copper residual . the user will preferably test the copper residual on a regular basis and maintain the copper residual between about 0 . 3 - 0 . 5 ppm by adjusting the control shaft 33 between an &# 34 ; off &# 34 ; position and a &# 34 ; full - on &# 34 ; position . at the end of the useful life of the electrodes , the electrodes will be eroded to the point that current will not flow between the electrodes 48 , and the &# 34 ; service required &# 34 ; light will be illuminated to indicate to the user that the electrodes need to be replaced . in the preferred embodiment , the electrodes 48 are replaced by replacing the electrode housing 14 . alternatively , the cap 50 , with integral electrodes 48 , could be replaced . the control shaft 33 setting required to maintain the residual copper within the desired operational parameters depends upon several factors , such as the usage / demand placed on the pool filter and the duty cycle of the pool pump . for example , and with all other parameters being constant , the more the pump runs , the lower the ionizer setting to maintain residual copper within the desired parameters . on the other hand , the less the pump runs , the higher the ionizer setting . the ionizer according to the present invention works as follows . when the pool pump is operating , vibrations caused by water flowing through the body 42 of the electrode housing 14 are transmitted through the enclosure 12 and detected by the vibration sensor 23 , causing the front circuit board to activate or power the electrodes 48 in an alternating fashion . the electrodes 48 will continue to be energized and supply ions to the water stream until vibrations are no longer sensed by the sensor 23 , meaning that the pump has switched off , and water is no longer being pumped through the electrode housing body 42 . when vibrations are no longer detected by the sensor 23 , the ionizer is de - activated . monitoring and sensing vibrations directly at the ionizer 10 provides several advantages . firstly , sensing vibrations ensures that each time the pump operates , power will be supplied to the electrodes to introduce ions , such as copper and silver ions , into the pool water to reliably maintain the copper residual within the desired parameters to help control algae , bacteria , and virus within the pool water . secondly , activating the ionizer dependent upon vibrations sensed remotely from the pump allows the ionizer to be reliably turned on / off without being directly wired to the pump . as such , the ionizer can be simply inserted or installed in the conventional swimming pool plumbing and plugged into a grounded household power outlet . this enables the ionizer according to the present invention to be retrofitted into existing pool installations . while the preferred embodiment of the present invention is shown and described herein , it is to be understood that the same is not so limited but shall cover and include any and all modifications thereof which fall within the purview of the invention .