Calcium hypochlorite compositions with transient color indicators and method of using the same

Abstract

A water treatment composition for treating a body of water is provided that provides visual feedback to the end-user of the effectiveness of the composition. The composition contains a majority of calcium hypochlorite particles; and an effective amount of colored particles containing an oxidizable pigment oxidizable dye and a water soluble material. The colored particles release the oxidizable dye to the body of the water to provide a transient color to the recreational water during dissolution of the composition in the body of water, the transient color providing a visual cue to the end-user signaling of the biocidal activity of the composition. Also provided is a method of applying the water treatment composition to recreational water.

We claim: 
     
         1 . A water treatment composition for treating a body of recreational water, the composition comprising:
 a majority of calcium hypochlorite particles; and   an effective amount of colored particles comprising, an oxidizable pigment, an oxidizable dye, a composition of an oxidizable pigment and a water soluble material, a composition of oxidizable dye and a water soluble material, or a mixture thereof;   wherein the colored particles release the oxidizable pigment and/or the oxidizable dye to the body of the recreational water to provide a transient color emanating from the composition to the recreational water during dissolution of the composition in the body of recreational water, the transient color providing a visual cue signaling biocidal activity of the composition to an end-user; and   wherein the composition is substantially free of surfactants to avoid foaming of the water.   
     
     
         2 . The water treatment composition according to  claim 1 , wherein the water treatment composition is granular, having particles of calcium hypochlorite and the colored particles. 
     
     
         3 . The water treatment composition according to  claim 1 , wherein the composition is a compacted tablet. 
     
     
         4 . The water treatment composition according to  claim 1 , wherein the colored particles comprise the oxidizable dye and a water soluble material. 
     
     
         5 . The water treatment composition according to  claim 4 , wherein the oxidizable dye is placed on the surface of the water soluble material. 
     
     
         6 . The composition according to  claim 5 , wherein the water soluble material comprises an inorganic salt, a gum or a resin. 
     
     
         7 . The composition according to  claim 6  wherein the water soluble material comprises an inorganic salt. 
     
     
         8 . The composition according to  claim 7 , wherein the inorganic salt comprises sodium chloride. 
     
     
         9 . The composition according to  claim 1 , wherein the water soluble material comprises a first water soluble material and a second water soluble material, and the oxidizable pigment and/or oxidizable dye is mixed with the second water soluble material to form a mixture, and the mixture is coated onto the first water soluble material. 
     
     
         10 . The composition according to  claim 9 , wherein the first and second water soluble material each comprise a salt. 
     
     
         11 . The composition according to  claim 9 , wherein the first and second water soluble material are each sodium chloride. 
     
     
         12 . The composition according to  claim 1 , wherein the colored particles comprise between about 0.1% by weight to about 10% by weight of the total weight of the composition. 
     
     
         13 . The composition according to  claim 12 , wherein the colored particles comprise between about 1% by weight to about 6% by weight of the total weight of the composition. 
     
     
         14 . The composition according to  claim 12 , wherein the oxidizable dye comprises between 0.01 and 2.0% by weight of the composition. 
     
     
         15 . The composition according to  claim 1 , wherein the calcium hypochlorite particles comprises between 60 and 99.9% by weight of the composition. 
     
     
         16 . The composition according to  claim 15 , further comprising up to 30% by weight, based on the total weight of the composition, of additional active components selected from the group consisting of water clarifiers, scale inhibitors, stabilizers, water softeners, corrosion inhibitors, algaecides, fungicides, binders, or a mixture thereof. 
     
     
         17 . The composition according to  claim 15 , further comprising:
 i) 0.1-20% by weight of magnesium sulfate heptahydrate;   ii) 0.01-10% by weight of aluminum sulfate; and   iii) 0.01-10% by weight of sodium hexametaphosphate.   
     
     
         18 . The composition according  claim 17 , wherein the composition comprises between 0.1% and 10% by weight of the colored particles. 
     
     
         19 . The composition according to  claim 18 , comprising:
 i) 75-85% by weight of the calcium hypochlorite;   ii) 2.0%-6.0% by weight of the colored particles;   iii) 10-20% by weight of magnesium sulfate heptahydrate;   iv) 0.1-2.0% by weight of aluminum sulfate; and   v) 0.1-2.0% by weight of sodium hexametaphosphate