| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide an economic water tank for exhibition not requiring a diver to dive in water and to clean the water tank, capable of positively collecting floating substances such as excretion, a remaining feed, etc., by utilizing a water current effect, not requiring a biofilter tank of separate placement. SOLUTION: This water tank 1 for exhibition comprises a tank main body 2, an organism filtration layer 3 laid at the bottom part of the tank main body 2, a supplementing water supply means 4 for supplying water to the tank main body, an upper water discharging means 5 for discharging water in the tank main body from the top part, an upper treating water supply means 6 for supplying treating water of discharged water to the tank main body 2 and an upper air supply means 7 for supplying air to the tank main body. A support 8 for supporting the organism filtration layer 3 is installed in the vicinity of the bottom part of the tank main body and a bottom treating water supply means 9, a bottom air supply means 10 and a lower part water discharging means 11 which is passed from the top of the organism filtration layer through the organism filtration layer and the support and extended to the bottom of the tank main body.</p> |
