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 phosphonocarboxylic acid copolymers or phosphonopolyacrylic acid homopolymers binding agents forming a dimensionally stable composition. Preferred phosphonocarboxylic acid copolymers or phosphonopolyacrylic acid homopolymers have phosphono end groups and a molecular weight of between about 1,000 and about 30,000 grams/mole. The stability enhancement composition for use in a solid detergent and solid detergent compositions are preferably biodegradable and substantially free of phosphorus and NTA-free.