Video Resource Library

How a Poly tank is Designed and Made


Polytanks appear to be a relatively simple product, however, it is highly engineered both from a design perspective and from the manufacturing process. Once the decision is made around the type and size of tank, round, slimline, square, etc., the tank is drawn up in a computer aided modeling system which allows for changes, but also does the engineering calculations. This program will allow the tank design to be adjusted until we are satisfied with the design once the design is finalized

The tank is modelled using a finite analysis program which confirms the thickness of walls, floor and roof. This includes the effect of any fittings. Once this is complete, then a steel mold is built in the shape of the tank manufacturing the poly tank, a poly tank, is made using the plastic molding process. This involves placing polyethylene powder, plastic, raw material into a mold and placing it in an oven. Heating it at the same time as it rotates as the plastic powder, raw material melts and sticks to the side of the tank mold. The rotating and the heating process determines the thickness of the tank, wall, floor and roof.

For example, a well designed and manufactured tank can have 100 percent thicker walls at the bottom of the tank wall and at the top of the wall. These differences in thicknesses will vary from product to product. And the important thing is, the manufacturing process is controlled to ensure the tank design comes out the same way every time. Once the heating process is complete, we then move to the cooling process. The doors open and the cooling process is underway. Once the tank has cooled, we go through the demolding process and then the mold is ready for the next tank to be made.

Every tank we make at Bushman’s is quality tested. We do an ultrasound test, a visual inspection, as well as sample testing. This asks the question, how do you know your poly tank is of the highest quality? It is important to choose a reputable supplier who’s been designing manufacturing tanks for some time. There is no substitute for experience and product in the field. Bushmans has had nearly 30 years as a certified manufacturer who has designed and manufactured their products to the Australian tank standard sets the benchmark for quality in this industry.

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    Bushman Tanks Guides You on How To Choose The Right Water Tank


    Today we’re going to walk through the steps to select the right tank for your house, your farm, or your commercial site.

    Australia is one of the driest continents on Earth, so water storage is critical. Installing a water tank to secure your water supply is a great risk protection strategy regardless of where you live. As an initial step, you need to select the size, type of tank and a suitable site for the tank to go on.

    Next, estimate how much water you need for a secure supply. This is determined by what the water is to be used for. Is it rainwater storage for your home, a stock water tank for the farm, or a storm water tank in an urban area.

    Where rainwater is to be harvested and stored, you need to make two calculations.
    1. How much water will your roof collect?
    2. How much water do you need for your house or garden?

    You can do this easily by first calculating the area of roof available in square metres, then check your annual rainfall in your local area. This can be done by searching the Bureau of Meteorology website, or search Bushmans as we provide a rainfall chart on our website.

    You will also need to estimate how many times your tank will potentially fill each year. Bushman’s have made these calculations easy for you. Go online to and you will find a water tank calculator showing what size tank would be required based on the amount of water that can be collected.

    The next step is to work out how much water you require. For example, if you’re a household of four, you need to know how much water you’re using in your bathroom, kitchen, laundry and garden over the course of the year.

    Once again, the Bushmans website has a calculator that will help estimate your water consumption. If you’re taking three years for livestock, your calculations will be different.

    You need to establish how much water you need to store or stock if there is an interruption to the water supply, such as a pump breaking down. For example, a dry cow drinks 35 daily litres of water per day. So let’s assume an average of about 60 litres per head per day. If you have 100 cows in a paddock relying on that tank, they will consume 6000 litres per day.

    If you want two to three days of water available, then your minimum tank size would be 15 to 20,000 litres. Calculations are an estimate only, as there are a lot of variables that can influence the amount of water you require and the amount of water which can be caught using rainwater harvesting.

    Once you’ve been through the process, you are now ready to order your new Bushmans tank.

    How To Prepare Your Base And Site For A Water Tank - Bushmans Tanks


    This how to video will show you the steps in preparing the base for your new poly tank.

    You’ve made a wise decision to install a water tank to secure your future water security. Whether your tank is for your home and garden or for stock, the preparation of the site and the base your tank will sit on is critical.

    To be effective, your new tank must be structurally secure on a solid base. There are a number of considerations you need to look at to decide what type of tank base you require. Commonly, your choices are a concrete slab, a sand or crushed dust base tank then, or in some cases, you may need to partially sink your tank into the ground.

    This is done to reduce the height the tank is above the ground. As you’re aiming to install the tank to secure your water supply at full capacity. The type of base you choose is determined by a number of factors. The cost, crusher dust or sand is a lower cost. Or you may require a concrete base or gravity fed water which would dictate a tank stand.

    Remember, water is heavy. A full tank is really heavy, 1000 litres of water weighs one tonne, so 30,000 litres of water weighs 30 tonnes. If you are putting in a tank say on a concrete slab, it needs to be designed by your engineer to carry the maximum weight. When designing your slab Bushmans recommend leaving at least 100 millimetres of space between the tank perimeter and the edge of the concrete slab.

    The most common form of tank base is a sand or crusher dust base. If this is your choice, ensure your material does not contain rocks or sticks, or other material that could penetrate the tank flow. Spread the sand or dust over the base to a depth of 50 to 75 millimetres, leaving a space of at least 300 millimetres around the diameter and the edge of the tank base ensuring all material is level and compacted.

    All tanks because of their weight require a firm base. Bushmans also recommends your base is boxed in reducing the risk of it being undermined or washed away. Timber sleepers or similar materials are an excellent longwearing choice for this. Many tanks are suitable for tank stands, however, it is important these stands like concrete slabs, are engineered to carry the weight of a full tank.

    If this then has a slatted floor or base it is important that gaps are more than 25 millimetres wide. There should also be at least 100 millimetres of space between the tank base and the edge of a tank stand floor.

    It goes without saying that the tank must be secured to the stand, both when it is full and empty. An ideal choice for this are hold down lugs. There are some situations where the tank needs to be partially in the ground. The maximum depth is no more than 1/3 of the tank wall height. The site should have the base excavated so there is a gap of 150 to 200 millimetres between the excavated wall and the tank wall. You need to ensure the excavated wall is stable.

    Then prepare the bass with concrete, crusher dust or sand as you would any other tank that sits above ground. It is important not to use soil taken from the hole. Spread a two to 300 millimetre layer of sand around the base of the tank and manually compact ensuring all voids are filled. Continue to do this until the void area is filled. Water inlet and outlet will be via the roof. Once you have the base prepared, you are ready to have the tank delivered and installed.

    How To Be Ready For Your Water Tank Delivery - Bushmans Tanks


    This how to video is to ensure that you are prepared, so your poly tank delivery runs smoothly.

    You have chosen your new tank size, colour, shape and location. The base is prepared and the truck is scheduled for delivery to your property. Now you need to be ready for the delivery and the subsequent siting and installation of your new tank.

    To ensure this is successful, you need to consider these four points.

    1. Is there a clear and sufficient access to the tank site?
    2. Where can the tank be rolled off on delivering? If equipment is required, then it needs to be ready on site.
    3. Are you ready with the plumbing and fittings?
    4. And can you safely secure your new tank

    Water tanks are large and there may be a need to clear a path allowing the delivery truck to get to the site. There needs to be a minimum of a 50 metre space where a truck and trailer combination can turn around.

    Consider any obstacles that a driver will need to deal with. These could include, low power lines, gates, inaccessible roads, roundabouts, crossing, overhanging trees, etc.

    The Bushmans delivery driver will need assistance at the time of delivery to unload your tank from the truck and our Bushmans website has useful information for you to understand what is required. If assistance is not possible other means such as a crane, front end loader will be required.

    All information is available in the Bushmans delivery and install guide. The bushmans delivery driver will brief on site helpers to support the unloading of the tank from the truck and the siting of the tank on the tank base.

    The most important part about this process is that it is done in a safe way so people and property are protected at all times. Check your site ahead of delivery to ensure it is possible to roll the tank off without damage. When moving the tank into position, avoid rough and sharp services, ensuring the area to unload the tank is level and clear of building material. Work health and safety requirements means the delivery driver cannot unload or move a tank to the installation site or leave the tank on site if insufficient assistance or unsafe access is provided.

    Our experienced drivers have the final decision on the safety and suitability of the site. There are a number of ways and steps in unloading the tank from the truck or trailer and the method used will depend on the site conditions. Ideally the site should be completely flat and clear. However, we know this is not always possible so we’ve developed processes to manage less than ideal conditions.

    This might mean lowering the tank from the truck using a strap. Once the tank is on the ground, it will be rolled to its final position. Once there, the tank is tipped up right and at this stage it is really important to have the support people who have been properly briefed to help lift the tank.

    Your new tank is now ready for the final fit out of the overflow and outlet. There are other things you need to plan and consider part of the tank installation process.

    These include the following:
    1. Do a check to ensure all plumbing and fittings are organised and onsite prior to delivery.
    2. Check with the local council for regulations relating to rainwater tank installations.
    3. See fittings and accessories on the Bushmans website for more information.
    4.Ensure allowances are made for the inlet overflow, pour outlets on your poly tank to move position slightly and expand and contract. Typical PVC or metal fittings are relatively rigid and inflexible.

    How To Manage The Final Installation Steps Of Your New Water Tank - Bushmans Tanks


    This video explains the final steps in the installation of your new poly water tank. Once your tank is properly cited, then the final fit out is undertaken so it is ready to hold water and secure your water supply. The location of the main hole will be positioned so water can simply be channeled through the strainer.

    If your tank is sourcing water from bores and wells, a strainer is located so it is easy to access. Bushmans tanks are designed so the final fit out can be done easily onsite. Location of the overflow and the tank outlet can be placed anywhere around the tank, ensuring it works well for you.

    Before the installation process is undertaken check to see the site is safe and that you have a ladder available to install the overflow and the strainer.

    The steps in the fit-out are:
    1. Choose where the outlet goes.
    2. Mark the outward position on your tank so it easily connects with pipes and pumps.
    3. Drill outlet holes to suit the tap or gate valve fitting you’re planning to use with a hole saw.
    4. Next use a hole saw to drill out the overflow, and the outflow must be positioned in the middle of the tank wall.

    Now we move to installing the outlet.
    1. Place the conduct in the overflow hole or strainer and feed it through to the drilled outlet hole.
    2. To insert the brass fitting into the outlet, undo the nut off the outlet and slide the outlet and the washer down the conduit.
    3. Pull it through from the outside.
    4. Screw the nut on tightly by hand, note this is a left-handed thread.
    5. Place thread tape into the outlet thread and fit the ball valve.
    6. Loosen off the hand tightened outlet nut and move the ball valve into the upright position.
    7. Turn the outlet nut with multi grips.
    8. Place the strainer back into the tank and back into place so it is sealed and vermin proof.

    To install the overflow.
    1. Insert the overflow elbow into the drilled hole until the seal touches the tank wall and screw it into place using the supplied screws.
    2. Push the mozzi screen or overflow strainer in the overflow outlet until it bottoms out.
    3. It is important that the tank is connected to the pipe or the pump using a flexible hose kit. This allows the tank wall to move as it fills and empties with water.
    4. Assemble the flex hose using thread tape and attach the elbow to the ball valve.
    5. Once you’ve installed the outlet, ball valve and the overflow, the tanke is ready to hold water and to be connected to pumps and pipes.

    Some simple hints included:
    Pipes to the main hole should allow at least 25 millimeters between the end of the pipe and the strainer. And ideally the pipe should be towards the center of the strainer. This will allow for the maximum effectiveness of the strainer and reduce the frequency of cleaning the strainer out.

    With the outlet, ball valve and flex hose in place, the tank can be connected to the pipe or pump. There is a need to ensure any digging or excavation around the tank base does not affect the integrity of the tank base.