embodiments of the invention are described herein in the context of a swimming pool , and particularly in the context of disinfecting the swimming pool water . however , it is to be understood that the embodiments provided herein are just preferred embodiments , and the scope of the invention is not limited to the applications or the embodiments disclosed herein . due to the above - mentioned disadvantages of using a halogen to treat water that contains both organic and inorganic contaminants , potassium monopersulfate ( khso 5 , herein referred to as pmps ) is sometimes used with halogen . pmps is effective at removing toc and prevents the accumulation of chloramines by allowing them to be oxidized via breakpoint chlorination . also , unlike chlorine , pmps does not produce thms . however , pmps has its disadvantages as well . for example , pmps is usually accompanied by an irritating byproduct , k 2 s 2 o 8 ( potassium oxodisulfate ). since bathers can tolerate only a low level of k 2 s 2 o 8 , there is naturally a limit to how much pmps can be added to a body of water . in applications such as swimming pools where the product may come into direct contact with bathers , pmps is added as part of a shock treatment whereby an entire dosage is spread across the surface of the pool at once . the dosage is limited to 1 ˜ 2 lb / 10 , 000 gallons per week , depending on the manufacturer . if this limit were to be exceeded , bathers are likely to experience irritation due to accumulation of k 2 s 2 o 8 , which has a long half - life . thus , this dosage cannot be exceeded regardless of how contaminated the pool water is . moreoever , the presence of the irritant means the pmps treatment must be performed when bathers are not present . most manufacturers of pmps - based pool treatment compositions require bathers to wait at least 30 minutes before using the pool after the treatment . the periodic shock treatment does not provide for sustained disinfection , and undesirably allows the water quality to fall between treatments . between pmps treatments , the organic and inorganic nitrogen in the water trigger competing reactions on the sanitizing / oxidizing agent , thereby impairing the disinfection rate . also , the competing reactions between accumulated organics and nitrogen for the sanitizing / oxidizing agent allow for increased levels of chloramines which impair both water and air quality . to address these issues , attempts have been made to use pmps in conjunction with a sanitizing agent , such as a halogen donor . however , a problem with pmps - and - halogen - based water treatment is that pmps is not compatible with some of the chlorine / bromine donor products that are most commonly used today ( e . g ., calcium hypochlorite , dichloro isocyanurate , trichloro - isocyanurate , bromo - chloro - dimethylhydantoin ( bcdmh ), dibromo - dimethylhydantoin ( dbdmh ). thus , to use pmps with a halogen , sophisticated control and applications technologies are need to be implemented to allow for more frequent feed of pmps while bathers are present . due to the incompatibility between pmps and halogen , these technologies feed the sanitizer and the pmps separately , and usually independently ( e . g ., see u . s . pat . nos . 6 , 620 , 315 , 6 , 409 , 926 , 6 , 143 , 184 ). in these processes , expensive chemical feed and control technology is required along with extensive on - site maintenance and expertise to tune in or optimize the sequencing of the chemicals being fed . the invention includes a pmps - halogen product including pmps and one or more halogen donors . the product overcomes the incompatibility problem between the pmps and halogen donors by implementing a barrier film between the pmps and halogen donor ( s ) which allows the pmps and the halogen donor to be combined into a stable composition . preferably , the product uses a pmps that is substantially free of k 2 s 2 o 8 so that more of the product can be used without posing a health hazard to the bathers . the pmps - halogen product frees up the halogen to react with inorganic wastes by having pmps remove organic wastes . the halogen - pmps composition contains 1 ) a halogen component that includes or produces a halogen donor , 2 ) a pmps component having the formula ( khso 5 ) x ( khso 4 ) y ( k 2 so 4 ) z , where x + y + z = 1 , x = 0 . 43 - 0 . 75 , y = 0 . 01 - 0 . 40 , z = 0 . 01 - 0 . 40 , and a k2s2o8 & lt ; 0 . 5 wt %, and 3 ) a barrier film between the pmps and the halogen components . the weight fractions of the pmps component , the halogen component , and barrier film are about 4 - 70 . 8 wt . %, about 29 - 95 . 8 wt . %, and about 0 . 2 - 10 wt . %, respectively . this halogen - pmps composition enhances disinfection rates by sustaining higher oxidation - reduction potential ( orp ) values in water that is being treated . furthermore , this halogen - pmps composition promotes breakpoint chlorination of organic nitrogen and of inorganic nitrogen in the presence of organic chemical oxygen demand ( cod ). in one embodiment , the pmps component has the formula ( khso 5 ) x ( khso 4 ) y ( k 2 so 4 ) z , where x + y + z = 1 , where x = 0 . 42 - 0 . 64 , y = 0 . 15 - 0 . 40 , and z = 0 . 15 - 0 . 40 . in another embodiment , the pmps component has the formula ( khso 5 ) x ( khso 4 ) y ( k 2 so 4 ) z , where x + y + z = 1 , where x = 0 . 48 - 0 . 64 , y = 0 . 15 - 0 . 37 , and z = 0 . 15 - 0 . 37 . the process for preparing this pmps component is described in u . s . provisional patent application ser . no . 60 / 505 , 466 , which is incorporated by reference herein in its entirety . the pmps component of the pmps - halogen product is made of about 43 to about 76 wt . % khso 5 , less than about 0 . 5 wt . % ( and preferably less than about 0 . 2 wt . %) of k 2 s 2 o 8 , and sometimes also alkali magnesium salt . depending on the embodiment , there may be no alkali magnesium salt in the product . the alkali magnesium salt comprises one or more of mg ( oh ) 2 , mgco 3 , mg ( hco 3 ) 2 , mgo , ( mgco 3 ) 4 — mg ( oh ) 2 - 5h 2 o , camg ( co 3 ) 2 , mgo — cao , ca ( oh ) 2 — mgo or combinations thereof . the halogen component is a substance that includes or generates a halogen donor , such as one or more of calcium hypochlorite , trichloroisocyanurate , dichloroisocyanurate , lithium hypochlorite , dibromo - dimethylhydantoin , bromo - chloro - dimethylhydantoin , sodium bromide , and sodium chloride . the barrier film , which may be an inorganic salt , silicate , borosilicate , an organic polymer , or any combination thereof , allows the halogen donor and the pmps composition to be combined . the inorganic salt may be one or more of sodium , potassium , magnesium , calcium , or a combination thereof , combined with one or more of carbonate , bicarbonate , hydroxide , oxide , silicate , borate , or combinations thereof . the silicate may be sodium , potassium , lithium , silicate , borosilicate , or a combination thereof . the organic polymer comprises chitin , chitosan , polymaleic acid , phosphinocarboxylic acid , carboxylate - sulfonate copolymer , a carboxylate - sulfonate terpolymer , or a combination thereof . the carboxylate component of the carboxylate - sulfonate copolymer or the carboxylate - sulfonate terpolymer is derived from either polyacrylic acid , polymethacrylic acid or polymaleic acid , and the sulfonate portion of the carboxylate - sulfonate copolymer or the carboxylate - sulfonate terpolymer is derived from an aliphatic or aromatic compound . the aliphatic compound comprises methacrylamido methyl propane sulfonic acid , and the aromatic compound comprises styrene sulfonic acid . the terpolymer incorporates a nonionic component such as ( meth ) acrylamide , substituted ( meth ) acrylamide , vinyl alcohol , allyl alcohol , vinyl esters , an ester of vinyl or allyl alcohol , styrene , isobutylene or diisobutylene . the barrier film may be coated onto either the halogen donor or the pmps composition . the barrier film may be coated by covering the composition with the barrier film material while mechanically mixing the barrier film material in a screw auger or a rotary drum . alternatively , the barrier film may be applied by using a fluidized driver . if the barrier film material is an inorganic salt , it may be applied before , during , or after the drying of the composition . if the barrier film material is silicate , borosilicate , and / or organic polymer , on the other hand , it is preferably applied to the composition either while the composition is drying or after the composition is dried . the coating is then applied in the form of a foam or atomized spray to maximize distribution , and further dried by using a suitable conventional drier including but not limited to a rotary drier or a fluidized drier . a halogen - pmps product containing the pmps composition and one or more of the halogen donors can effectively control the chloramine , cod , and toc levels in the treated water and reduce or even eliminate the problems associated with the accumulation of these undesirable products . further , the halogen - pmps composition reduces or eliminates any byproducts resulting from incomplete oxidation of the waste . this composition may be in powder form , granular form , or in the shape of a pellet , nugget , tablet , sphere , briquette , puck , etc . the halogen component functioning as the halogen oxidizer may be calcium hypochlorite , trichloroisocyanurate , dichloroisocyanurate , lithium hypochlorite , dibromo - dimethylhydantoin , bromo - chloro - dimethylhydantoin , sodium bromide , sodium chloride , or a combination thereof . the pmps compound used for the pmps - halogen product has a k 2 s 2 o 8 byproduct concentration below 0 . 5 wt . % and preferably below 0 . 2 wt . %. the low k 2 s 2 o 8 concentration allows the pmps - halogen product to be used at a higher dosage than what is currently allowed . in fact , the pmps - halogen product may be used continually while the pool is being used . the composition can then be shaped into a useful solid form by using established processing techniques . if the composition is granular , it may be produced using rotary mixers and / or rotary driers . alternatively , a spray graining technique may be used with a fluidized drier . if the composition is a tablet , a nugget , a briquette , a sphere , a puck or a solid object of a different shape , it may be produced by combining and mixing the components of the composition and applying pressure to a mold or extruding the objects of the desired shape . optionally , a well - known binding agent may be used to enhance the cohesiveness of the particles . the pressure level that is applied during extrusion may be adjusted according to the desired hardness of the end product . the shaped composition ( e . g ., a tablet ) is inserted into a feeder or a strainer at any location in the pool , or into a pool circulating system that is continuously or periodically immersed in the water to be treated . the pmps - halogen product is preferably released in a controlled manner . besides a tablet , some exemplary shapes for the pmps - halogen product include powder , granules , nugget , briquette , pucks , etc .— anything deemed suitable by a person skilled in the art . the disclosed stable composition can then be employed in water treatment applications as an improved disinfectant . the pmps - halogen product may be used in a liquid form . to prepare the liquid form of pmps - halogen product , the solid form of pmps - halogen product is dissolved in water using any number of dry product feed devices . for example , a tank with a mixer and a pump may be used . alternatively , a chemical feeder which contains the pmps composition may be used to dissolve some or all of the composition before using the solution . using the chemical feed , the composition may be applied by periodically using a timer , or by manually or automatically activating the feed system . the method allows for frequent incremental feed or continuous feed of the composition even when bathers are present , without concern of causing irritation . “ frequent incremental feed ,” as used herein , refers to a feed of at least one cycle per day . when the pmps - halogen composition is used to treat water that contains bathers &# 39 ; waste , the concentration of chloramines and other undesirable byproducts is sustained at much lower levels than when the components of the composition are used separately . furthermore , when the pool water is “ shock ” treated by addition of the powder or granular composition across the surface of the pool , the combined level of chlorine and other undesirable contaminants is reduced to a level much lower than that achieved using current methods of shock treatment or breakpoint chlorination . also , with the halogen - pmps composition of the invention , there is no need for an oxidation reduction potential ( orp ) control device of the type disclosed in u . s . pat . no . 6 , 620 , 315 . optionally , various other additives such as ph buffering agents , coagulants , clarifiers , algae control agents ( e . g ., boron or lanthanum based additives ) may be included in the halogen - pmps composition without deviating from the scope of this invention . although preferred embodiments of the present invention have been described in detail hereinabove , it should be clearly understood that many variations and / or modifications of the basic inventive concepts herein taught which may appear to those skilled in the present art will still fall within the spirit and scope of the present invention .