A SUBSIDIARY HOT-WATER CIRCUIT 



IN AN AQUARIUM FED BY AN OPEN CIRCUIT 



By L. Barriety 



Musec dc la Mer, Biarritz, France 



Abstract. — An effective method is described for recirculating and filtering heated sea 

 water, in order to alleviate the thermal loss entailed when warmed water is wasted. 



One of the disadvantages of supplying 

 an aquarium with sea water using an open 

 circuit is the lack of flexibility from the 

 thermal point of view. The temperature 

 at which the water is received in such an 

 installation is closely related to the tem- 

 perature of the sea water at the point 

 where it is pumped, and if for any rea- 

 son — for instance, maintenance of tropical 

 fish or of organisms from polar regions — 

 it is necessary to heat or cool the water, 

 this conditioned water will be drained off 

 almost entirely, without any practical pos- 

 sibility of recovery. 



But in these temperate regions it fre- 

 quently occurs that subtropical animals 

 may be caught from the sea, and if one 

 desires to keep them alive for several years 

 it becomes necessary to supply them with 

 heat during the winter. If they are small, 

 and if the tank where they live is rather 

 small, one may be content to heat the water 

 by any means (the most frequently used 

 means is an immersion heater) and to let 

 the w^armed water go down the drain, since 

 the weak output does not involve a very 

 considerable expenditure of heat. Things 

 are entirely different in the case of large 

 animals requiring tanks that are some- 

 times tens of cubic meters in size. In such 

 a case, the recovery of the water after it 



This paper was prepared in French ; it was trans- 

 lated Into English by a commercial translating service. 



has passed through the tanks affords a sub- 

 stantial saving of heat and is therefore 

 necessary. This procedure is used in the 

 turtle (Caretta caret fa) tank of the 

 Musee de la Mer at Biarritz, which has 

 a volume of 18 cubic meters. 



To mamtain sufficient limpidity in the 

 tank, it is necessary to ensure a more or 

 less total renewal of the water every 24 

 hours, and the daily consumption is close 

 to 15 cubic meters. On the other hand, 

 to provide good living conditions for the 

 turtles, the water temperature must be 

 maintained at 17° to 18° C. In midwinter 

 the water comes from the reserve tanks 

 at 10° to 11° C. and is heated in a heat 

 exchanger to 18° C. before it is introduced 

 into the exhibit tank, which it leaves at 

 a temperature of 17° C. It is this water 

 that is drained off, with a consequent loss 

 of the magnitude of 75 therms; this rep- 

 resents, for just one tank, a very consider- 

 able waste. 



Accordingly, we have considered it ap- 

 propriate- to alleviate that loss as much as 

 possible by recovering the water and re- 

 using it after filtration. Consequently, 

 for this turtle tank, a separate circuit was 

 installed at the outlet of the exhibit tank 

 A (fig, 1) which includes a filter with two 

 compartments, a heat exchanger, and a 

 rotary pump which accelerates the circula- 

 tion. The most interesting element of this 



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