Tandem type breeding box and breeding method for breeding white spotted pike

Abstract

The invention discloses a tandem type culture box and culture method for white spot dog fish culture, the tandem type culture box comprises a water storage tank, a culture unit and a circulation box, the water storage tank is internally provided with a water storage cavity, the water storage tank is provided with a heating element, the water storage tank is communicated with the culture unit, water in the water storage tank can be introduced into the culture unit, the culture unit is communicated with the circulation box, and the circulation box is communicated with the circulation box. Water in the cultivation unit can be fused into the circulation box, a neutralization cavity is formed in the circulation box, the water storage tank is provided with a stirring unit and a neutralization port, one end of the neutralization port is communicated with the neutralization cavity, the other end of the neutralization port is communicated with the outside of the water storage tank, the stirring unit is used for stirring water in the neutralization cavity, and the circulation box is communicated with the water storage tank. And water in the circulating box can be introduced into the water storage box. Through continuous heating of the water storage tank and cooperation with water circulation, water constant temperature control is achieved, the influence of external temperature fluctuation on growth of the white spotted pike is eliminated, and it is guaranteed that the growth environment is stable.

Description

Technical Field

[0001] This invention relates to the field of aquaculture equipment technology, and in particular to a series-connected aquaculture tank and aquaculture method for raising pike. Background Technology

[0002] In the process of breeding white pike culter pedigrees, juvenile fish of the same pedigree need to be placed in the same net cage to avoid mixing with fish of other pedigrees.

[0003] In the prior art, Chinese patent document with authorization announcement number CN212414358U discloses a breeding cage for the Lanzhou catfish family, including an outer cage and an inner cage. The outer cage is fixedly installed in the breeding pond, and the inner cage is installed inside the outer cage. The inner cage can slide relative to the top edge of the outer cage. The inner cage includes a sliding connecting rod and a detachable cage. The sliding connecting rods are arranged opposite each other, and the two ends of the sliding connecting rods are locked at the top edge of the outer cage and can slide along the top of the outer cage. The detachable cage is fixed on the sliding connecting rod and is located below the sliding connecting rod and inside the outer cage.

[0004] Existing breeding cages are highly susceptible to changes in ambient temperature, making it difficult to maintain a suitable temperature range for the growth of pike, resulting in insufficient stability of the breeding environment. Therefore, it is necessary to improve this structure to overcome these shortcomings. Summary of the Invention

[0005] The purpose of this invention is to provide a series-connected culture tank and culture method for the cultivation of pike, which solves the problem that existing breeding net cages are greatly affected by environmental temperature, making it difficult to maintain the suitable growth temperature range for pike and resulting in insufficient stability of the culture environment.

[0006] The above-mentioned technical objective of this invention has been achieved by the following technical solutions:

[0007] A series-connected culture tank for raising pike includes a water storage tank, a culture unit, and a circulation tank. The water storage tank has a water storage cavity inside and is equipped with a heating element for heating the water in the storage cavity. The water storage tank is connected to the culture unit, and the water in the water storage tank can flow into the culture unit. The culture unit is connected to the circulation tank, and the water in the culture unit can flow into the circulation tank. The circulation tank has a neutralization cavity inside. The water storage tank is equipped with a stirring unit and a neutralization port. One end of the neutralization port is connected to the neutralization cavity, and the other end of the neutralization port is connected to the outside of the water storage tank. The stirring unit is used to stir the water in the neutralization cavity, and the neutralization port is used to add a reagent to neutralize the water. The circulation tank is connected to the water storage tank, and the water in the circulation tank can flow into the water storage tank.

[0008] A further configuration of the present invention is as follows: the cultivation unit includes at least two cultivation tanks, each cultivation tank having a cultivation chamber for accommodating pike. Adjacent cultivation tanks are connected by a pump unit 1, which is used to transport water between adjacent cultivation tanks. One cultivation tank is connected to a water storage tank via a pump unit 2, and the other cultivation tank is connected to a circulation tank via a pump unit 3.

[0009] A further feature of the present invention is that the water storage tank and the circulation tank are connected by a pump unit four, which is used to realize the water transport between the water storage tank and the circulation tank.

[0010] A further feature of the present invention is that the heating element is a heating tube, the heating element is installed on the water storage tank, and the heating end of the heating element is located inside the water storage cavity.

[0011] A further feature of the present invention is that the stirring unit includes a stirring motor and a stirring rod. The stirring motor is mounted on the circulation tank, and the stirring rod is located in the neutralization chamber. The stirring motor is connected to the stirring rod and is used to drive the stirring rod to rotate. Multiple stirring blades are mounted on the stirring rod, and the stirring blades can rotate synchronously with the stirring rod.

[0012] A further feature of the present invention is that the incubator is provided with a drain pipe, one end of which is connected to the incubation chamber and the other end of which is connected to the outside of the incubator, and an on / off valve is installed on the drain pipe.

[0013] A further feature of the present invention is that pump unit one, pump unit two, pump unit three, and pump unit four have the same structure and all include a water pump, with an inlet pipe installed at one end of the water pump and an outlet pipe installed at the other end of the water pump.

[0014] A series-connected culture tank and culture method for raising pikeperch, comprising the following steps:

[0015] Step 1: Install the series-connected breeding boxes in the predetermined position and inject initial breeding water into the water storage chamber of the water storage tank; then, inject some water into the first breeding box through pump unit 2, and inject water into the subsequent series-connected breeding boxes in sequence through pump unit 1, until the breeding chambers of all breeding boxes and the neutralization chamber of the circulation box reach the normal working water level;

[0016] Step 2: Activate the heating element on the water tank to heat the water in the storage chamber, and monitor the water temperature in real time through the water temperature monitoring device; adjust the heating power to make the water reach and maintain a stable temperature range required for the cultivation of pike.

[0017] Step 3: Start pump unit 2 to continuously pump the heated and regulated water from the storage tank into the first incubation tank; then start each pump unit 1 in sequence to make the water flow through the incubation chambers of each incubation tank set in series at a predetermined flow rate, so as to realize the synchronous flow-water culture of pike in multiple incubation tanks; then, pump unit 3 discharges the water from the end incubation tank into the neutralization chamber of the circulation tank.

[0018] Step 4: After the circulating water flow stabilizes and the water temperature reaches the standard, release the pike fry into each rearing tank; according to the breeding specifications, feed the fish regularly and in measured quantities through the feeding port on the top of each rearing tank, and observe the feeding and activity status of the fish.

[0019] Step 5: Periodically add water conditioner through the neutralization port on the circulation tank, then start the stirring unit to drive the stirring rod and stirring blades to fully stir and mix the water and reagent in the neutralization chamber to neutralize harmful substances and adjust the pH value;

[0020] Step Six: Start pump unit four to pump the treated water in the circulation tank back to the storage tank, mix it with the water in the storage chamber, and reheat and regulate it, thus forming a closed loop of storage tank → incubation tank → circulation tank → storage tank.

[0021] In summary, the present invention has the following beneficial effects:

[0022] 1. The water tank is continuously heated and circulated to achieve constant temperature control of the water, eliminating the impact of external temperature fluctuations on the growth of pike and ensuring a stable growth environment.

[0023] 2. The recycled water is neutralized through a circulation tank to improve water quality regulation efficiency and maintain dynamic water quality balance.

[0024] 3. The multi-breeding tanks are connected in series, and each breeding chamber can independently accommodate juvenile fish of different families. The water between adjacent tanks can be controlled and transported, which is convenient for adjustment according to different breeding conditions. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of the present invention.

[0026] Figure 2 This is a structural diagram of the water storage tank.

[0027] Figure 3 This is a schematic diagram of the circulation tank.

[0028] Numbering: 1. Water storage tank; 2. Circulation tank; 3. Water storage chamber; 4. Heating element; 5. Neutralization chamber; 6. Neutralization port; 7. Incubation box; 8. Incubation chamber; 9. Stirring motor; 10. Stirring rod; 11. Stirring blade; 12. Drain pipe; 13. On / off valve; 14. Water pump; 15. Water inlet pipe; 16. Water outlet pipe. Detailed Implementation

[0029] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below with reference to the figures and specific embodiments.

[0030] like Figures 1 to 3 As shown, the present invention proposes a series-connected breeding tank for raising white-spotted pike, comprising a water storage tank 1, a breeding unit, and a circulation tank 2. The water storage tank 1 has a water storage cavity 3 inside and is equipped with a heating element 4 for heating the water in the water storage cavity 3. The water storage tank 1 is connected to the breeding unit, and the water in the water storage tank 1 can flow into the breeding unit. The breeding unit is connected to the circulation tank 2, and the water in the breeding unit can flow into the circulation tank 2. The circulation tank 2 has a neutralization cavity 5 inside and is equipped with a stirring unit and a neutralization port 6 in the water storage tank 1. The stirring unit is used to stir the water in the neutralization cavity 5, and the neutralization port 6 is used to add a reagent to neutralize the water. The circulation tank 2 is connected to the water storage tank 1, and the water in the circulation tank 2 can flow into the water storage tank 1.

[0031] The system comprises the following components: Storage tank 1 (a sealed container with a storage chamber 3 made of stainless steel) stores water to be heated; heating element 4, a component that raises the water temperature (using a heating pipe); circulation tank 2 (a water treatment container with a neutralization function, also made of stainless steel, with a neutralization chamber 5 containing water to be treated); stirring unit (a mechanical structure for liquid mixing, using a motor-driven paddle structure; the paddles create vortices within the neutralization chamber 5 to promote reagent diffusion); and neutralization port 6 (a channel for adding chemical reagents, which can be a funnel-shaped interface with a sealed cap). During use, heating element 4 in storage tank 1 provides basic heating to the water in storage chamber 3, and the heated water is then transported to the cultivation unit. After the water in the cultivation unit completes its aquaculture operations, it flows into the neutralization chamber 5 of circulation tank 2. The stirring unit then mechanically stirs the water in neutralization chamber 5, and the pH adjuster added through neutralization port 6 neutralizes the water. The treated water flows back to the storage tank 1 through a circulation pipe, forming a closed loop. This circulation path continuously replenishes the water temperature within the storage tank 1, while the circulation tank 2 eliminates factors that degrade water quality, achieving a dynamic balance between temperature and water quality. Compared to existing technologies, this application achieves continuous constant temperature control of the aquaculture water, effectively eliminating the impact of external temperature fluctuations on the growth of pike. Water circulation reduces the frequency of water replacement, and the combination of chemical treatment and physical stirring in the neutralization chamber 5 improves water quality regulation efficiency.

[0032] The cultivation unit includes at least two cultivation tanks 7, each with a cultivation chamber 8 for accommodating pike. Adjacent cultivation tanks 7 are connected by a pump unit 1, which is used to transport water between adjacent cultivation tanks 7. One cultivation tank 7 is connected to a water storage tank 1 via a pump unit 2, and the other cultivation tank 7 is connected to a circulation tank 2 via a pump unit 3.

[0033] The cultivation tank 7 is a container with an independent cultivation chamber 8 inside, used to house juvenile pike from different families, preventing crossbreeding. Pump unit one is a water delivery device connecting adjacent cultivation tanks 7, using a centrifugal pump with an inlet pipe 15 and an outlet pipe 16 to facilitate water exchange between adjacent cultivation tanks 7 through directional delivery. Pump unit two is a delivery device connecting the first cultivation tank 7 to the storage tank 1, used to introduce heated water from the storage tank 1 into the cultivation tank. Pump unit three is a delivery device connecting the last cultivation tank 7 to the circulation tank 2, used to guide water from the cultivation tank into the circulation tank 2 for water quality neutralization. Multiple cultivation tanks 7 are connected in series via pump unit one, forming a tiered water circulation path. Hot water in the storage tank 1 is delivered to the first cultivation tank 7 via pump unit two, then flows sequentially through adjacent cultivation tanks 7, and finally enters the circulation tank 2 via pump unit three. During this process, the water flow between adjacent cultivation tanks 7 is controlled via pump unit one. After the circulating tank 2 neutralizes the returned water, it can be transported back to the storage tank 1 to form a closed-loop circulation system.

[0034] The water storage tank 1 and the circulation tank 2 are connected by a pump unit 4, which is used to realize the water transfer between the water storage tank 1 and the circulation tank 2.

[0035] Heating element 4 is a heating tube, which is installed on the water storage tank 1, with the heating end of heating element 4 located inside the water storage cavity 3. The heating end of the heating tube is directly immersed in the water in the water storage cavity 3, raising the water temperature through contact heat conduction. The heating tube is fixed to the outer wall or top of the water storage tank 1, specifically through a threaded sealing structure, which ensures the overall sealing of the equipment and facilitates the inspection and replacement of the heating tube.

[0036] The stirring unit includes a stirring motor 9 and a stirring rod 10. The stirring motor 9 is installed on the circulation tank 2, and the stirring rod 10 is located in the neutralization chamber 5. The stirring motor 9 is connected to the stirring rod 10 and is used to drive the stirring rod 10 to rotate. Multiple stirring blades 11 are installed on the stirring rod 10, and the stirring blades 11 can rotate synchronously with the stirring rod 10.

[0037] The stirring motor 9 is a device that generates rotational power through electric drive. Specifically, it can be implemented using a waterproof DC motor. Its output shaft is connected to the stirring rod 10 to transmit torque. The stirring rod 10 is a rigid rod extending into the neutralization chamber 5. The stirring rod 10 is used to support the stirring blades 11 and transmit rotational motion. The stirring blades 11 are sheet-like structures fixed to the stirring rod 10. The stirring blades 11 generate water flow shear force through rotation to accelerate mixing and ensure that the water flow in the neutralization chamber 5 is uniformly mixed under the action of mechanical stirring.

[0038] The incubation tank 7 is equipped with a drain pipe 12. One end of the drain pipe 12 is connected to the incubation chamber 8, and the other end of the drain pipe 12 is connected to the outside of the incubation tank 7. An on / off valve 13 is installed on the drain pipe 12. The on / off valve 13 is triggered to open according to water quality monitoring data or water change requirements, so that deteriorated water is discharged in a directional manner through the drain outlet to prevent abnormal growth of pike due to cross-contamination or local water quality deterioration.

[0039] Pump Unit 1, Pump Unit 2, Pump Unit 3, and Pump Unit 4 have the same structure, all including a water pump 14. One end of the water pump 14 is equipped with an inlet pipe 15, and the other end is equipped with an outlet pipe 16. The water pump 14 is the power unit used for water transport. The inlet pipe 15 is the pipe connecting to the inlet end of the water pump 14, and can be a PVC pipe with a flange or threaded interface, used to guide the water to be transported into the pump body. The outlet pipe 16 is the pipe connecting to the outlet end of the water pump 14, and can be a pipe structure symmetrically arranged with the inlet pipe 15, used to export the pressurized water to the target container.

[0040] The usage process and principle of this invention are as follows: In use, sufficient aquaculture water is injected into the water storage tank. Then, the heating element in the water storage tank is activated to heat the water to a temperature suitable for the growth of pike. The heated water is then pumped from the storage tank to the rearing tank via pump unit two. Water is sequentially pumped between adjacent rearing tanks via pump unit one, ensuring all rearing tanks are filled with heated water. Next, juvenile pike from different families are placed into their respective rearing tanks for daily feeding, observation, and other aquaculture management. When water needs to be changed, the pike are removed, and the water from the final rearing tank is pumped to the neutralization chamber of the circulation tank via pump unit three. The stirring unit is activated, and reagents are added through the neutralization port to adjust the water quality. The treated water is then returned to the storage tank via pump unit four, with the heating element replenishing heat, forming a closed-loop cycle of "storage tank → rearing unit → circulation tank → storage tank". If the water quality in a rearing tank deteriorates, its drain valve is opened to discharge the deteriorated water.

[0041] Example 1:

[0042] This embodiment provides a series-connected culture tank for breeding juvenile pike, including a water storage tank 1, three series-connected incubation tanks 7 (7a, 7b, and 7c respectively), and a circulation tank 2.

[0043] The outlet of water storage tank 1 is connected to the inlet of the first incubator 7a via water pump P1. Incubators 7a and 7b are connected via pump unit P2, and 7b and 7c are connected via another pump P3. The outlet of the last incubator 7c is connected to the inlet of the circulation tank 2 via water pump P4. The outlet of the circulation tank 2 is connected back to the inlet of water storage tank 1 via water pump P5, forming a closed loop.

[0044] The water storage tank 1 is equipped with a heating element 4, set to a constant temperature of 22±0.5℃, which is the suitable growth temperature for juvenile pike. The top of the circulation tank 2 is equipped with a stirring motor 9 that drives the stirring rod 10 and blades 11, and the side wall has a neutralization port 6. Each incubation tank 7 has a drain pipe 12 with an on / off valve 13 at the bottom.

[0045] Workflow: Start all water pumps, and the water circulates along the path: storage tank 1 → incubation tank 7a → incubation tank 7b → incubation tank 7c → circulation tank 2 → storage tank 1. Periodically add a trace amount of sodium bicarbonate solution to circulation tank 2 through neutralization port 6. The stirring unit operates to maintain the water pH between 7.8 and 8.2. The three incubation tanks 7a, 7b, and 7c can each house juvenile pike from different families. The interconnected water flow ensures environmental consistency and comparison, while physical isolation prevents mixing of families. The structure is simple and low-cost, effectively solving the core requirements of temperature control and anti-mixing in parallel multi-strain cultivation, making it suitable for research or small-scale hatcheries.

[0046] The core objective of the temperature control method is to provide and maintain a constant, uniform, and suitable water temperature environment (e.g., 22±0.5℃) for the growth of juvenile pike (Pike chuatsi). Temperature-controlled water flowing from the storage tank passes sequentially through each of the rearing tanks. This continuous flow of water constantly carries heat into each tank and replaces the slightly cooled old water, thus bringing the water temperature in all tanks close to the outlet temperature of the storage tank. The series design ensures that the water flowing through each tank has the same heat source and undergoes the same process, fundamentally guaranteeing a high degree of temperature consistency between the different rearing tanks.

[0047] Centralized heating is more efficient and results in less heat loss than heating each incubator individually.

[0048] The goal of pH control methods is to maintain a stable pH level within the aquaculture system (e.g., 7.8-8.2) to neutralize acidic substances produced by fish metabolism and uneaten feed decomposition. A pH sensor is installed at the inlet or inside the circulation tank to monitor the pH level of the water flowing into the rearing unit in real time. By actively removing acidic substances that cause pH drops, the water quality is kept stable, significantly reducing the need and cost of frequent water changes in traditional aquaculture. Temperature control and pH control are two independent yet collaborative core processes: temperature control is centered on the storage tank, and both are tightly coupled through a closed loop formed by the same pump and piping, creating an intelligent aquaculture system that dynamically maintains a constant temperature and water quality environment. This perfectly meets the research and production needs of species selection and other fields requiring high environmental consistency.

[0049] In the description of this invention, it should be noted that the terms "upper," "lower," "inner," "outer," "left," and "right," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use, or the orientation or positional relationship commonly understood by those skilled in the art. These terms are used only for the convenience of describing this invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. Furthermore, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance. In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, terms such as "set" and "connect" should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances. In this document, the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, which includes not only the elements listed but also other elements not expressly listed.

[0050] Any descriptions not covered in the above specific embodiments of the present invention are known technologies in the field and can be implemented with reference to such known technologies.

[0051] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A series-connected culture tank for raising pike, characterized in that, The system includes a water storage tank, a cultivation unit, and a circulation tank. The water storage tank has an internal water storage cavity and is equipped with a heating element for heating the water in the storage cavity. The water storage tank is connected to the cultivation unit, allowing water from the storage tank to flow into the cultivation unit. The cultivation unit is connected to the circulation tank, allowing water from the cultivation unit to flow into the circulation tank. The circulation tank has an internal neutralization cavity. The water storage tank is equipped with a stirring unit and a neutralization port. The stirring unit is used to stir the water in the neutralization cavity, and the neutralization port is used to add a reagent to neutralize the water. The circulation tank is connected to the water storage tank, allowing water from the circulation tank to flow into the water storage tank.

2. The series-connected culture tank for raising pikeperch, as described in claim 1, is characterized in that, The cultivation unit includes at least two cultivation tanks, each containing a cultivation chamber for accommodating pike. Adjacent cultivation tanks are connected by a pump unit, which is used to transport water between adjacent cultivation tanks. One cultivation tank is connected to a water storage tank via a second pump unit, and the other cultivation tank is connected to a circulation tank via a third pump unit.

3. A series-connected culture tank for raising pikeperch, as described in claim 2, is characterized in that, The water storage tank and the circulation tank are connected by a pump unit four, which is used to realize the water transfer between the water storage tank and the circulation tank.

4. A series-connected culture tank for raising pikeperch, as described in claim 1, is characterized in that... The heating element is a heating tube, which is installed on the water storage tank, with the heating end of the heating element located inside the water storage cavity.

5. A series-connected culture tank for raising pikeperch, as described in claim 1, characterized in that, The stirring unit includes a stirring motor and a stirring rod. The stirring motor is mounted on the circulation tank, and the stirring rod is located in the neutralization chamber. The stirring motor is connected to the stirring rod and is used to drive the stirring rod to rotate. Multiple stirring blades are mounted on the stirring rod, and the stirring blades can rotate synchronously with the stirring rod.

6. A series-connected culture tank for raising pikeperch, as described in claim 2, is characterized in that, The incubator is equipped with a drain pipe, one end of which is connected to the incubation chamber and the other end of which is connected to the outside of the incubator. An on / off valve is installed on the drain pipe.

7. A series-connected culture tank for raising pikeperch, as described in claim 3, is characterized in that, Pump unit 1, pump unit 2, pump unit 3, and pump unit 4 have the same structure and all include a water pump. One end of the water pump is equipped with an inlet pipe, and the other end of the water pump is equipped with an outlet pipe.

8. A series-connected culture tank and culture method for raising pike, comprising the following steps: Step 1: Install the series-connected breeding boxes in the predetermined position and inject initial breeding water into the water storage chamber of the water storage tank; Subsequently, a portion of the water is injected into the first incubation tank through pump unit two, and water is injected into the subsequent incubation tanks in series through pump unit one until the incubation chambers of all incubation tanks and the neutralization chamber of the circulation tank reach the normal operating water level. Step 2: Activate the heating element on the water tank to heat the water in the storage chamber, and monitor the water temperature in real time through the water temperature monitoring device; adjust the heating power to make the water reach and maintain a stable temperature range required for the cultivation of pike. Step 3: Start pump unit 2 to continuously pump the heated and regulated water from the storage tank into the first incubation tank; then start each pump unit 1 in sequence to make the water flow through the incubation chambers of each incubation tank set in series at a predetermined flow rate, so as to realize the synchronous flow-water culture of pike in multiple incubation tanks; then, pump unit 3 discharges the water from the end incubation tank into the neutralization chamber of the circulation tank. Step 4: After the circulating water flow stabilizes and the water temperature reaches the standard, release the pike fry into each rearing tank; according to the breeding specifications, feed the fish regularly and in measured quantities through the feeding port on the top of each rearing tank, and observe the feeding and activity status of the fish. Step 5: Periodically add water conditioner through the neutralization port on the circulation tank, then start the stirring unit to drive the stirring rod and stirring blades to fully stir and mix the water and reagent in the neutralization chamber to neutralize harmful substances and adjust the pH value; Step Six: Start pump unit four to pump the treated water in the circulation tank back to the storage tank, mix it with the water in the storage chamber, and reheat and regulate it, thus forming a closed loop of storage tank → incubation tank → circulation tank → storage tank.

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