September 22, 2021

Everyone loves a bargain, and no one likes getting their wallet fleeced. So naturally, when making investment decisions we want to be as frugal as possible without compromising too much on quality.

Most growers have been in the game for years… tanks, troughs, tractors, tools, boom sprays and harvesters. They know what these things are worth. However, when it comes to things like reverse osmosis (RO) membranes and high-pressure pumps on variable speed drives… these are things many farmers are less familiar with.

Which is no surprise, it’s information, technology, and equipment that is often only relevant to desalination and sophisticated water irrigation systems.

By asking these questions you’ll have more clarity as to what differentiates the quality products from the lemons offered out there…

DISCLAIMER: I have included figures and explanations based on Moerk Water’s standard practice. These may vary.


Operating Costs

1.     What are the consumables, spare and wear parts, and how frequently will they need replacing?

There are several consumables in sophisticated desalination/water treatment systems. On our systems these include:

–        Cartridge filters

o   Replace 2-4 times per year, $10-$50 AUD each

–       Media (for the media filter)

o   Replace after 3-20 years, cost depends on the size of the system and type of media used

–       Antiscalant (to prevent scaling and fowling of the membranes)

o   Depending on the feedwater quality, operating hours, and capacity of the system

–       Seal kit for the pumps

o   Depending on the size and operating hours of the system

–       CIP cleaning chemicals

o   1-2 times per year. Depending on the feedwater quality and size of the system

2.     How much will it cost to change the membranes, how long do they typically last? (If looking at a reverse osmosis system)

The membranes in our systems last 7-10 years and cost typically between $600-$1650 AUD each (depending on the brand, type, and size). They can be replaced by the client following our instructions or we can supply them to you.

3.     What is the operating power required to run the system?

This will depend on the capacity, recovery rate, and salinity level. We can also utilize energy recovery technology by leveraging the discharge pressure. Please contact our team for more information on this.

4.     Are you willing to guarantee these numbers?

It is our philosophy that we design and build a product that is made to last. We can at our clients’ request offer a guarantee around the operating costs we propose.


 Component Quality

5.     What brand of pumps are used and where are they made?

We primarily use Grundfos pumps in our systems, it is a Danish company that produces reliable high-quality products that many farmers are familiar with. And because it can be locally sourced this also can help in the event it needs servicing or a component needs to be replaced. 

6.     Does the system use a variable speed drive?

In most cases our pumps operate using variable speed drives, this allows for the system to operate optimally and allows the pressure to build slowly in the high-pressure pump (the pressure going through membranes typically varies between 20-60 bar) it also helps in a shutdown and flushing sequence to reduce the stress on the system and specifically the membrane(s).

7.     How does the automation and control mechanisms in the system work?

Many systems on the market are either manual or semi-automatic and need to be turned off and on. Be aware of semi-automatic advertised as automatic.

Our systems are automatic and remain on standby and operate according to various sensors throughout the system. For example, we use level sensors in the feed and product water tanks. On our solar powered units, they are additionally controlled by the battery status of charge.

8.     What type of piping is used?

Reverse Osmosis (RO) systems require high pressure, and therefore require high-pressure piping. Many cheaper systems compromise on this to lower capital costs.

In most cases, we use Schedule 80 uPVC piping to keep the system robust and compatible with a broad range of available fittings to ensure durability and ease of service.

9.     What is the life expectancy of the system?

We design our systems to last 20 years. However in all honesty, the answer to this is like answering the question “How long does a car last?”. Part of it depends on the servicing and the operating hours but as a rule of thumb higher-quality units last for longer.

On our systems, we monitor the need for servicing through remote monitoring or by a client-maintained manual log sheet.

10.  What other costs are involved in a successful installation of the system, and what does the ongoing support look like?

Our systems are standalone and complete and designed to allow for changes in feedwater quality within a range, as feedwater quality does often change over time. Furthermore, we communicate to the client upfront what other infrastructure will be required for the project to operate successfully. We have an excellent track record because we do this. There are no additional upsells or hidden costs.


Recovery rate

11.  What percentage of the water will be recovered as a result of the treatment? 

Many off-the-shelf systems have a standard, fixed recovery rate that binds the buyer to a particular product quality and yield. 

We optimise the recovery rate based on feed-water quality and the client’s preferences and needs. This optimises capital and operating costs. When the feedwater is a limited supply, and/or you want to minimise the volume of discharge produced, it can be useful to have a higher recovery.

12.  What will the waste product / effluent composition be?

In our RO systems, the effluent will be a concentration of the feedwater inputted into the system. The concentration will be higher or lower depending on the recovery rate. In some instances, the effluent quality can be manipulated to be suitable for livestock or salt-tolerant plants.


There can be a big difference between something that delivers a result, and something that works well for the long haul.

The truth is, there are sub-par off-the-shelf water treatment systems and gimmicks going around.

Look, some of these products may work for some purposes… but when it comes to something like reverse osmosis, all it takes is a bit of silica or iron and suddenly you’ll be facing all kinds of woes if you have an ill-design system that wasn’t built bespoke to your water quality. Consequently, you’ll be bleeding out paying for all the servicing required.

The easiest solution to navigating the space of water treatment is to get a thorough water analysis by an accredited lab and then consulting with an expert so you know exactly what needs to be done.

If you are sick, you go to the doctor to get an accurate diagnosis, from there he can prescribe you different options.

A water treatment consultant is like a doctor for your ‘sick’ water.

We diagnose your water analysis and prescribe solutions based on the water chemistry and your desired end result. To do anything less than this, would be a disservice to our clients.

Which is why almost all our systems are designed a built fit-for-purpose. We prefer not to offer off-the-shelf products.

So whether you decide to work with us or not on your water treatment project, we recommend getting your water analysed through us and making the most of a free consultation with our team.

The benefit of doing this is you will be aware of the ideal water treatment method based on the exact specifications of your water.

So even if you decide to go ‘price shopping’ later for a cheaper off-the-shelf option (if you can find one) … you’ll at least know what the gold-standard solution is.

Moerk Water systems really are the top-end of the market; German-Australian engineering, locally manufactured and built to last.

Our background has mostly centered around remote international projects that have necessitated us to build durable, low-maintenance, easy-to-service systems.