Stability enhancement agents for use in a solidification matrices and solid detergent compositions are described. Stability enhancement is provided by a hydratable salt, water and a carboxylic acid terpolymer forming a dimensionally stable solid compositions. Preferred carboxylic acid terpolymers include from about 40 to 90% by weight of a carboxylic acid monomer, anhydride or salt thereof, from about 4 to 40% by weight of a monomer comprising sulfo groups, and from about 4 to 40% by weight of a nonionic monomer set forth in formula (I). The stability enhancement composition for use in solid detergent compositions are preferably biodegradable and may be substantially free of phosphate and/or NTA-free and provide beneficial hard water scale control.