A method for treating a recirculating water 
system which comprises introducing into said water 
system a multifunctional, 
multilayer tablet, wherein the 
multilayer tablet comprises a fast dissolving layer and a slow dissolving layer, wherein said fast dissolving layer releases a combination of active ingredients including a member selected from the group consisting of 
lithium hypochlorite, 
calcium hypochlorite, 
trichloroisocyanuric acid (TCCA), 
anhydrous sodium dichloroisocyanurate, 
sodium persulfate, 
potassium persulfate, 
potassium monopersulfate, 
sodium monopersulfate, and mixtures thereof, and at least one of a 
clarifier, chelating agent, sequesterant, algaestat, water softener, 
algaecide, 
corrosion inhibitor, scale inhibitor, flocculent, disintegrant, dispersant, colorant, 
dissolution control agent, fragrance, or surfactant and, wherein said slow dissolving layer includes a member selected from the group consisting of 
trichloroisocyanuric acid (TCCA), 
calcium hypochlorite, 1,3-dichloro-5,5-dimethylhydantoin (DCDMH), 1,3-dibromo-5,5-dimethylhydantoin (DBDMH), 1-bromo-3-chloro-5,5-dimethylhydantoin (
BCDMH), 1,3-dichloro-5-ethyl-5-methylhydantoin (DCEMH), 1,3-dibromo-5-ethyl-5-methylhydantoin (DBEMH), 1-bromo-3-chloro-5-methyl-5-ethylhydantoin (BCEMH), and mixtures thereof, and at least one of a 
clarifier, chelating agent, sequesterant, algaestat, water softener, 
algaecide, 
corrosion inhibitor, scale inhibitor, flocculent, disintegrant, dispersant, colorant, 
dissolution control agent or surfactant.