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Introducing the Sealed Tank System

The rain water harvesting industry enters a new era.

What has been ‘good enough’ for decades can no longer meet today’s customer requirements. Wrigglers and the occasional frog in unsealed rain water tanks were accepted as part of life, as much as the famous red back spider under the toilet seat was, while sludged up rain water tanks were considered as unavoidable as the next drought.

But times have changed. The rain harvesting industry was presented with new demands to old problems and consequently new products have been developed. Who could have imagined 10 years ago that stainless steel rain water tanks would be the dominating force in the market?

Our customers have expressed again and again, the explicit wish to keep their tanks clean and eliminate the constant annoyance of having to use dirty rain water tanks. In fact, if there is one ‘disadvantage’ with a stainless steel water tank, it is the ability to show up any floaties in the water because of the unique sparkling clean surface which highlights even the smallest contaminants.

Over the years, extensive discussions were held and many hours were spent looking at ideas to keep metal water tanks unconditionally clean. New products were examined, but none offered a satisfactory solution. Slowly the idea crystallised that the only way to ensure that the tank would remain clean, is to seal the tank to any foreign matter. No more inlet strainers, but a sealed and screwed lid instead.

The idea of the Sealed Tank System was born

Unfortunately, the realisation that the storage water tanks have to be sealed to remain absolutely clean was only the first step in the development of a working rain harvesting system. Some of the major obstacles to overcome were the amount and nature of the contamination, in particular; leaves, small branches, and small to very minute dust particles.

The various gadgets, (which should remain nameless) that are promoted to keep your tanks clean, are simply not up to the task. No fifty dollar attachment can successfully separate and treat the amount of water entering a water storage tank during a major rain event, not even in a minor rain fall.

Owners of rain harvesting systems are well aware of the continuously blocked and overflowing inlet strainers and the associated and frustrating loss of water, not to mention the irritation of trying to clear the inlet strainer during a rain storm. Not just once, but a couple of times.

We examined all these issues and leaned heavily on the experience of homeowners who depend on rain water. Answers were found, prototypes were built and tested in real life situations, which concluded in the Sealed Tank System.

The Main Components of the Sealed Tank System

Essentially there are 4 main components:

  • The Separation, Collection and Transfer tank (which we will refer to as SCT)
  • The Transfer Pump
  • The Filtering Station
  • And the Storage Tank


Function of the SCT Tank

function_1Separation: Water enters the tank via multiple down pipes without the hindrance of any strainers. The Tank has a huge internal stainless steel screen fitted, which separates all large debris (such as leaves and branches) from the stream of water. The screen is inclined, facilitating a self cleaning effect and terminates in a discharge outlet. The gigantic inclined screen cannot clog up.

function_2Rainwater collection: The pre cleaned water falls through the screen and collects on the bottom of the tank. The water level then rises and activates a level switch.

Transfer: The level switch activates the high volume pump and forces the water through the main filter and into the storage tank.

Purpose of the transfer pump

purpose_1Every system has a pump sized correspondingly to the particular collecting roof. The pump has to be capable to keep up with the inflow into the SCT tank.

In simple terms, small roof = small pumps and large roof = large pumps. The pump also has to be powerful enough to force the water through the jumbo filtering station. Forced filtering is one of the key elements in the whole system. No more gravity feeding through a miniature tank inlet screen.

Purpose of the filtering station

Only filtered water is clean water. Of course rain as it falls from the sky (strictly speaking) is distilled water, but on ‘the way down’, it collects dust and other undesirable particles.purpose_2

Other contaminants are also absorbed into the water during run off from the collection (roof) area. To return the water into its original, pristine condition, these contaminants have to be filtered out prior to entering the storage tank.

Attempts to achieve this goal were made with the introduction of a simple filter bag, which is a large textile bag hanging into the tank below the inlet strainer. This idea functioned reasonably well for the first couple of hundred litres entering the tank, but the bag was totally overwhelmed when attempting to filter anything more than 1000 litres of water. It simply clogged up and water spilled over the tank. In addition, the bag cannot be removed during a rain storm, it is simply too heavy to be lifted from the tank, as it holds more than 100 litres of water.

purpose_3The task could only be handled by a gigantic jumbo filter with not less than 56 square meters of filtering area. And even with this size of filter, the support of a powerful transfer pump is required to achieve the desired result. Finally, the cleaned water is forced into the sealed storage tank past a non returnable valve. This valve ensures no water can flow back into the filter.

Features of the Sealed Tank System

Just about all rain water tanks can be retrofitted with the sealed tank system. Of course, it is essential to get your tank cleaned out professionally, prior to installation.

A gauge on the filter housing will indicate when the cartridge requires cleaning. The cartridge can be cleaned by means of a sharp stream of clean water and will give many years of service.

Every system is custom built to suit your particular situation. Please indicate your roof size for firm quotations.

We do not recommend our Sealed Tank System for small rain water tanks where the water is used to refill the pool, clean the car or water the garden. This is a commercial system designed for large water tanks, where the water is used for potable applications.

Roofs over 500 square meters require special consideration. Please contact us for advice

We can arrange installation of the system, if required, but any handyman could do the pipe work. One word of caution, a licensed electrician is required to connect the level switch on the SCT tank to the mains power supply.

Also, please be aware, that on the rare occasion that a rain event combines with a power failure, the system will not work. Although the down pipes can be fitted in such a way to bypass the system (by using a 3 way valve), we do not recommend this option as the rain water harvesting tank will be contaminated with unfiltered water. It would be the lesser evil to lose some water, than to have to clean out a tank, which has been kept clean for years.

In the case that your Queensland water tank has to be refilled with reticulated (town) water, this can be done by simply unscrewing the sealed lid on the storage water tank. Please ensure the lid is refitted tightly after the refill.

Another one of the unique features of the sealed tank system is that your storage water tank can be higher than your roof guttering!

But by far the most important aspect of our Sealed Tank System is the fact that it actually works properly!

If you are not prepared to compromise with the cleanliness of your rain water tank then there is no other option.

You are welcome to inspect our display system in our workshop. Please contact us on (07) 5546 8571 to make an appointment or if you need additional advice.

Sealed Tank System Installed

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If you would like more information on rain harvesting or help picking the best rain water tank for you, please call us on (07) 5546 8571.