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Why a Single Rainbow Reservoir Tank rather than Plastic Tanks

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Why should I install a single Rainbow Reservoir tank instead of a number of plastic tanks?

Water tanks supplied by rainbow Reservoirs

There are several reasons why a single, bolted-panel steel tank from Rainbow Reservoirs is preferable over a number of polyethylene plastic tanks making up the same volume:


The cost of a single Rainbow Reservoirs tank is significantly less than a number of plastic tanks making up a similar volume.


Vessel Capacity (litres) Approximate Cost (ZAR)
Rainbow Reservoirs Tank Model HT115/2 52 000 50 000.00
2 x 20,000L + 1 x 10,000L plastic vertical tanks 50 000 85 000.00


A lack of adequate space is often an important factor when installing liquid storage systems. When space is restricted, the installation of single, Rainbow Reservoirs tank requires much less space than an array of smaller tanks making up the same volume.


Vessel Capacity (litres) Surface area (m²)
Rainbow Reservoirs Tank Model HT115/6 156 000 22,57
Eight x 20,000 litre plastic vertical tanks 160 000 58,32

Tanks provided by Rainbow Reservoirs


Rainbow Reservoir Tanks are all fitted with a galvanised steel roof (included in the price of the tank). This dome-shaped roof, when fitted with our optional gutter system, provides a large surface area perfect for harvesting rainwater directly into the tank. Polyethylene plastic tanks are not suitable as stand-alone rainwater-harvesting vessels.


In areas that are prone to extreme temperatures, one large body of water is more resistant to extreme temperature fluctuations than smaller volumes retained in small water tanks.


One professionally built steel tank of elegant design is aesthetically far more appealing than a number of smaller plastic tanks (often lumped together in a clutter of different brands, sizes, colours and shapes).


The large, steel-panel surface of our Rainbow Reservoir tanks may be utilized as a “billboard”, providing an ideal surface for high-impact, visual advertising. In this regard, some of our tanks may have a diameter of 19m while others have a height of almost 7m – perfect advertising space!

Range of Water Tanks by Rainbow Reservoirs


When opting for the installation of number of plastic tanks, each tank requires at least two plumbing connections in order to connect the tanks as a large-volume unit. These inter-tank connections are prone to temperature and pressure stresses as the tanks fill or empty. These stresses often cause the inter-tank connections to fail resulting in constant leaking at the connection points.


When an array of plastic tanks is installed directly on the ground without a base, grasses and weeds often take root between the tanks, most especially when a welcome water source is provided by leaking inter-tank connections. This is not only unsightly, it also requires more time and effort to clean between the tanks and their inter-tank connections.


The volume of materials utilized in the construction of several smaller tanks is far greater by comparison, than the materials required to construct a single tank of the same volume.

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