62 



MAINTAINING FISHES 



good deal of aeration can be accomplished by this 

 means. 



The air-lift type water pump is widely used by 

 aquarium hobbiests. It is simple and inexpensive, and 



6. Agitator for aerating aquaria and hauling tanks, 



each tank may be equipped with a separate pump. 

 Its principal application is in low pressure filtration of 

 small tanks. The principle of the air-lift pump is il- 

 lustrated in Figure 7. 



Another pump of considerable use in aquarium 

 work is a small, submersible type centrifugal. These 

 are available in capacities as low as 82 gallons per 

 hour and pressures equal to 7 feet of head. For drain- 

 ing unusually large tanks a household type, submersi- 

 ble, sump pump is very effective. The next best choice 

 is a self -priming centrifugal. In most cases piston and 

 centrifugal pumps which are not self -priming are not 

 satisfactory. 



