36 



J. E. McINERNEY AND W. S. HOAR 



A. SALT WATER AQUARIA 



B. AERATORS 



C. WATER SUPPLY TO PUMP & FILTER 

 D- SELF-PRIMING PUMP & MOTOR UNIT 



E. FLOAT ACTIVATED PUMP SWITCH 



F. FILTER BED 



G. COOLING COILS 

 H. FILTERED WATER RETURN 



Figure 1. — Salt-water system : A, salt-water aquariums : B, aerators ; C, water supply to pump and 

 filter; D, self-priming pump and motor unit; E, float-activated pump switch; F, filter bed; 

 G, cooling coils ; H, filtered-water return. 



suitable nontoxic material. Two types 

 are illustrated in figure 2. Successive 

 layers of finer and finer gravel beginning 

 with the coarsest gravel or rock at the bot- 

 tom provides the least expensive method 

 of filtration (fig. 2, i). Cleaning this fil- 

 ter bed involves running fresh w^ater into 

 the bottom and up through the sand and 

 gravel to the top of the tank (fig. 2,3) to 

 waste through an overflow outlet (fig. 2, 



4). 



A simpler disposable filter is made from 

 two thicknesses of industrial fiberglass 

 battens (fig. 2, 2) mounted on an appro- 

 priate frame. The frequency with which 

 the fiberglass must be washed or changed 

 will depend mainly on the number of ani- 

 mals in relation to the surface area of the 

 filter bed. 



TEMPERATURE 



With a closed salt-water system there 

 must usually be some means of keeping the 

 water sufficiently cool. The simplest and 

 least unsightly method is illustrated in fig- 

 ure 2. A supply of cold tap water is circu- 

 lated through plastic or, for more efficient 

 heat transfer, stainless-steel coils mounted 

 below the fiberglass filter bed (fig. 2, 5). 

 With a graded-rock filter the coil may be 

 included directly in the filtering material. 

 More precise temperature control may be 

 achieved by using either a complete re- 

 frigeration system or by operating a 

 thermostatically controlled heater in op- 

 position to a continuous source of cooling 

 such as the cold-water coils suggested 

 above. 



