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developed by G. H. Nancollas in 1964, described in Nancollas, G. Hand Koutsoukos, P. G. "Calcium Phosphate Nucleation and Growth in solution." Prag. Crystal Growth Charact. 3, 77-102 (1980) can be used. This system consists of measuring the growth rate of calcium phosphate crystals seeded with hydroxyapatite ([Cas(PO$_{4}$ ) $_{3}$OH] or HAP) in the presence of CaC1$_{2 }$ and NaH$_{2}$PO$_{4}$ . Calcium phosphate growth liberates protons that can be titrated with a strong base. The amount of base needed to keep the pH constant over the crystal growth enables persons skilled in the art to measure the crystal growth rate directly as well as to determine the effects of potential crystal growth rate inhibi› tors. A typical plot of such an experiment is given below: 

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The observed t-lag value defines the efficiency of a compound to inhibit the growth of calcium phosphate crys› tals; wherein the higher the t-lag, the better the CGI. 

The following procedure can be used to build the plot given above experimentally: 

Place 350 mL of distilled water ( distilled twice), 35 mL of KCl 2.lM, 50 mL of CaC1$_{2 }$ 0.0175M and 50 mL of KH$_{2}$PO 4 0.01M in a reaction vessel. Insert a glass pH electrode and a standard calomel reference electrode connected to an auto-titrator. Bubble nitrogen gas and stabilize the tempera- ture of the reaction mixture to 37° C. When temperature and pH are stabilized, add the CGI candidate at the concentration to be tested (e.g. 1.10- $^{6}$M). Titrate to pH 7.4 with KOH 0.05M. Then seed the reaction mixture with 5 mL of hydroxyapatite slurry [Cas(PO$_{4}$)OH]. 

The hydroxyapatite slurry is prepared as follows: 

100 gr of Bio-Gelfi HTP hydroxyapatite powder is dis› persed in 1 L of distilled water. The pH of the resulting slurry is lowered to 2.5 by dropwise addition of HCl 6N. This is then heated to boiling and refluxed while stirring for seven days in a 2 L round-bottom flask connected to a condenser. After cooling, to room temperature, pH is adjusted to 12.0 by dropwise addi› tion of 50% Na OH and the slurry is refluxed for another seven days as before. The slurry is allowed to settle for to days and the supernatant is suctioned off. The flask is refilled with 1.5 L of distilled water, stirred vigorously, an allowed to settle again for two days. A total of seven rinses as described above are performed. The pH is adjusted to 7.0 by dropwise addition of HCl 2N while stirring vigorously. The resulting slurry is stored at 37° C. for eleven months. 

The plot shown above is obtained by recording the amount of base added over time to maintain the pH of the reaction medium. T-lag for a particular crystal growth 65 inhibitor is determined graphically as described in the figure above. 

The crystal growth inhibitors to be used for the purpose of this invention have a t-lag of at least 10 minutes at a concentration of 1.10- $^{6}$M, preferably at least 20 minutes, most preferably at least 50 minutes. 

Still another suitable method for determining the crystal growth inhibition property of the selected component which is comparable to the T-lag method is by a visual grading. The method is as follows: 

A multicycle laundry test is performed over several (e.g. 10) cycles of repeated washing and tumble drying. The conditions used are representative for the desired geographi› cal region (e.g. domestic washing machine used, detergent used, rinse added product use, water hardness, clothing articles washed etc.). At least two test legs are run in parallel, including the composition of the invention and a separate reference leg. After the required number of washing cycles have been performed the test garments (articles of clothing) are taken for comparison by expert graders under controlled lighting conditions. The visual grading is a better/worse comparison of the visible crystalline residue on the surface of the test garments, comparing the test leg to the reference leg. Dark coloured, knitted cotton articles are most suitable for this comparison. 

In addition, the crystal growth inhibitors, differentiate themselves from the chelating agents by their low binding affinity for copper defined by its Log K, i.e the ML/M.L Log Kat 25 C., 0.1 ionic strength, of the CGI is of less than 15, preferably less than 12. 

Preferably, the CGI for use in the present invention are selected from carboxylic compounds, organic monophos› phonic acids, organic diphosphonic acids, and mixtures thereof. 

Carboxylic Compounds 

Typical of carboxylic compound for use herein are the carboxylic compounds selected from glycolic acid, phytic acid, monomeric polycarboxylic acids, homo or copoly› meric polycarboxylic acids or their salts in which the polycarboxylic acid comprises at least two carboxylic radi› cals separated from each other by not more than two carbon atoms. 

When utilised in salt form, alkali metals, such as sodium, potassium and lithium, or alkanolammonium salts are pre› ferred. 

Organic detergent CGis suitable for the purposes of the present invention include, but are not restricted to, a wide variety of polycarboxylate compounds. As used herein, "polycarboxylate" refers to compounds having a plurality of carboxylate groups, preferably at least 3 carboxylates. Poly- carboxylate CGI can generally be added to the composition in acid form, but can also be added in the form of a neutralised salt. When utilized in salt form, alkali metals, such as sodium, potassium, and lithium, or alkanolammo› nium salts are preferred. 

Included among the polycarboxylate CGis are a variety of categories of useful materials. One important category of polycarboxylate CGis encompasses the ether polycarboxylates, including oxydisuccinate, as disclosed in U.S. Pat. Nos. 3,128,287 and 3,635,830. See also "TMS/ TDS" CGis of U.S. Pat. No. 4,663,071. Suitable ether polycarboxylates also include cyclic compounds, particu› larly alicyclic compounds, such as those described in U.S. Pat. Nos. 3,923,679; 3,835,163; 4,158,635; 4,120,874 and 4,102,903. 

Other useful CGI include the ether hydroxypolycarboxylates, polyacrylate polymers, copoly› mers of maleic anhydride with ethylene or vinyl methyl ether, or acrylic acid, 1,3,5-trihydroxy benzene-2,4,6- 

