A NEW FORMULA FOR ARTIFICIAL SEA WATER 



By Richard Segedi and WiKiam E. Kelley 



The Cleveland Aquarium, Cleveland, Ohio 



Abstract. — An artificial substitute for sea water is offered which has performed well 

 in keeping both vertebrates and invertebrates at the Cleveland Aquarium. The formula 

 is assembled and stored for convenient use as a 4-part preparation. 



The use of artificial sea water is nearly 

 as old as the keeping of marine aquariums. 

 In 1854, Gosse, who was one of the prin- 

 cipal popularizers of the home aquarium, 

 both fresh-water and marine, described his 

 experiences with simple mixtures of 

 readily available chemicals that could be 

 used when natural sea water proved too 

 difficult to procure. 



This was hardly a year after the open- 

 ing of the world's first public aquarium in 

 London. A few unsuccessful experiments 

 with synthetic sea water were subsequently 

 carried out in some of the early aquariums, 

 but the first institution to use it with any 

 success appears to have been the Berlin 

 Aquarium, which opened to the public in 

 1869. The recipe was a simple one, involv- 

 ing only four salts, and, like the mixtures 

 concocted by Gosse, it required an inocu- 

 lation of seaweed or some similar living 

 organisms to make it fit for higher forms 

 of marine life (Hoffmann, 1884). If the 

 great success claimed for this Ersatzsee- 

 loasser was not at all exaggerated, it is diffi- 

 cult to find any reason why most aquariums 

 did not evenutally adopt it. However, 

 very few institutions have found artificial 

 sea water to be a satisfactory substitute for 

 the natural product, one noteworthy ex- 

 ception being another Berlin aquarium, 

 w^hich opened to the public in 1913, as de- 

 scribed by Heinroth (1937). 



Several different formulas for artificial 

 sea water have been devised (table 1). 

 The number of ingredients in them varies 

 from 4 to 14, but the avowed purpose of 

 them all was to provide as close a facsimile 

 as possible to actual sea water. 



THE BACKHAUS FORMULA 



In December 1960, one of us (Kelley) 

 visited the Exotarium of the zoological 

 gardens of Frankfurt am Main, and while 

 there was most favorably impressed with 

 both the practical and the theoretical as- 

 pects of the synthetic sea water that had 

 been prepared by Dr. Dieter Backhaus of 

 that institution. Dr. Backhaus' approach 

 to the problem had not been to try to imi- 

 tate natural sea water, but to produce the 

 artificial medium in which marine animals 

 would thrive best, regardless of how close- 

 ly it might or might not resemble the com- 

 position of sea water in nature. It was 

 recognized that the synthetic mixture 

 would have to resemble natural sea water 

 at least in the rough proportions of its 

 principal salts, but these were only taken 

 as a general guide in the first formulations. 

 The appearance and behavior of the many 

 marine fishes and invertebrates on exhibi- 

 tion at the Exotarium attested to the 

 soundness of the new approach, and Dr. 

 Backhaus graciously made his formula 

 available to us for further experiment. 



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