THE AQUARIUM BUDLDING 



25 



Water 



LEVEL 



OVERFLOW 

 WATER — 



IWIInWIIIIIh 



•OVERFLOW 



.LARGER PfPE PLACED 



OVER OVERFLOW PIPE 

 CAUSES WATER TO RISE 

 FROM BOTTOM OF TANK 



y-^UBBER 6T0PPE« 

 / /-ORAIM 



5. Sectional view of a gravity drain and overflow for 

 fish tanks. 



Compressed Air 



An aquarium building should have a com- 

 pressed air supply throughout. Each tank should have 

 a valve and two or more should be available for larger 

 tanks. Since this air supply is of fairly low pressure, 

 at least three-quarter inch galvanized steel pipe 

 equipped with needle valves is recommended. Other 

 t^'pes of valves do not permit the degree of control of 

 air flow that is desirable. The compressor should be a 

 high-volume, low-pressure type. The need is for a 

 constant air supply, hence a tank equipped \\dth a 

 pressure swdtch is not desirable. It is more satisfactory 

 to permit the compressor to run continuously. All of 

 these requirements are best met by an oilless, rotary 

 pump. Most conventional piston pumps have a high 

 pressure, low volume characteristic and are not satis- 

 factory (see also section on Aeration). For a small 

 number of tanks one may use any one of a number of 

 small diaphram or piston pumps designed for aquar- 

 ium use. 



