| 摘要 |
An aquarium with fresh water supply above for growing large quantities of fish in a minimum of space. A screen across aquarium confines fish to upper levels and prevents them from mixing descending waste particles below with fresher water above. Slanted bottom of aquarium converges to an adjustable outlet through which sediments are forced by the weight of water above. An air pump releases bubbles at end of tubing near screen to aerate water and create circulation causing contaminants to fall by gravitational and centrifugal forces. A ball valve with float closes outlet when water level falls too low. A siphon and auxiliary tank prevents overflow. Fresh water entering presses water with contaminants away from fish through screen below and out of discharge opening, removing pollutants and replacing water at required intervals to permit the crowded fish to grow for years. A filter retards the return of the heavier particles of pollutants and nitrogenous substances to the space occupied by the fish. A small propeller aerator strengthens the circulation.
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