8 facts about the coating of our metal water tanks

Did you know?

  • We always advise to get the bottom ring panels of the water tanks coated or painted.
  • The application of a powder coating increases protection of the steel against the elements. It helps to protect the metal from rust and thus extends the lifetime of a water tank.
  • The panels can be ordered precoated; that is easy! If panels are ordered coated, they apply a layer of powder coating to the precious steel of the bottom rings at the factory.
  • As many as panel rings desired can come coated. Customers can even opt for an entirely coated tank.
  • Especially in coastal environments or industrial settings where the atmosphere has higher salinity, chemicals or natural pollutants, a coating is highly recommended.
  • Powder coating is available in a wide range of colours.
  • Also a metal roof can be coated in the desired colour.
  • A coating allows tanks to blend into the natural scenery. Some customers opt for this reason for an entirely (pine green) coated tank, benefiting from a high esthetic value.
Want to learn more about the coating of our metal water tanks? Contact us!

The future of water conservation

This summer shows it yet again; extreme weather is becoming the new normal. From heat records in southern Europe, to floods and typhoons in Southeast Asia, and from destructive wildfires in America to persistent drought in Africa.

Water plays a central role. Alongside increasingly longer droughts, rainy seasons are becoming shorter and, in most cases, are accompanied by extremely heavy rains. Most of that rainwater is lost through surface runoff as there often is little infrastructure to collect the water for when it is most needed: during dry periods. In this respect, water – and the lack of it – connects us; we have a role to play. Everyone has a role to play.


One of the main sources of water for greenhouse operations is groundwater from wells. Groundwater wells are often overused, with several associated and unsustainable consequences in the long term. Alternative water management approaches are needed.

Rainwater harvesting

Sustainable use of water could maintain a balance between its demand and supply. Rainwater harvesting is the most traditional and sustainable method. It is the practice of collecting and storing rainwater and make it available for later, where and when there is a scarcity of water. Typically for irrigation, but also for agriculture, livestock, and domestic purposes. We have supplied several water tanks to projects where they have been collecting rainwater for flushing water in facilities (project in Thailand, project in India, project in the Netherlands).

Advantages of rain water harvesting

  • Conserves water
  • Promotes water self-sufficiency
  • Reduces costs. It ensures less reliance on more expensive sources of water. Only a system to harvest rainwater into a water tank has to be installed. However, many facilities already perfectly qualify for rainwater harvesting; with angled roofs, gutter and irrigation systems already in place.
  • Reduces drainage problems on a property and runoff. This results in less soil erosion and surface water on site.
  • Rainwater is normally of good quality, making it a high-quality water source.
  • Relieves underground water wells. Pumping up groundwater is expensive, of lower quality and besides it severely harms the ecosystem.


The availability of adequate amounts of water is crucial for growing crops. Crops’ necessity of water can easily exceed the supply that is available. With roof drains and gutters, growers have the opportunity to collect large quantities of rainwater that can be used for crop irrigation.

Rainwater storage

There are various types of water harvesting techniques: traditional and modern ones. What they all have in common is that a decent system where the rainwater can be stored is key. That is where NPI plays a role. We make fresh and safe water available. How? By producing and exporting water storage systems, including excavated basins and metal water tanks.

Why water tanks?

  • Large capacity on small area
  • Made to measure: many capacities and diameters available
  • Control over quantity and quality of water
  • Modular, so installable in remote areas
  • Easy transport
  • Easy installation
  • High quality: a long lifetime


In some cases or seasons, water tanks cannot collect all the rainwater that falls, resulting in nearly always overloaded water tanks. When no overflow is installed, the excess water in the tank seeps down the tank walls. The water will not leave the metal corroded but moisture marks will appear when water frequently overflows. Despite the good quality of galvanisation, we always recommend our customers to install an drain pipe for overflow.

Water tank in Malaysia with no overflow installed
Want to learn more about our water tanks for rainwater harvesting? Contact us!

Promoting high-quality and sustainable development of the horticultural industry

Since the beginning of this year, our water storage solutions are exposed in the Horti Innovation Center at Beijing. This demonstration park serves as an exchange platform for the horticulture industry. Internationally renowned companies and horticultural research institutions work together in the center, showcasing the latest innovations, technologies and results of scientific research.

The center includes several functional areas: a flower demonstration area, an agricultural science and technology info exchange area, an AI flower factory laboratory, a horticulture exhibition area and info exchange areas. Demonstrating processes as automation in horticulture, vertical farming and fertilization.

NPI water tanks at Horti Innvation Center in Beijing

The Horti Innovation Center also aims to provide a communication platform for these companies and help them enter the Chinese market and bring more potential customers. The Chinese horticultural sector shows a huge potential, but foreign companies often face challenges such as the lack of customers and ignorance of local policies. The Innovation Center provides these companies with localized information and help them expand the Chinese market.

Since the establishment of the park, it has already welcomed thousands of visitors. Including horticultural professionals, local investors, influential media in China, international delegations, governments, heads of state and leading politicians.

Obviously, irrigation is unmissable in this concept and our water storage solutions fit perfectly in this high-tech and sustainable demonstration park. Several NPI water tanks were installed in the center and in the exhibition area a booth is installed with more information about our water storage solutions.

If you have been following us for a while, you might have come across him here. Gonçalo; dealer, business partner and friend in Portugal. Let’s introduce him!


Gonçalo Tavares, 43 years old, currently living in Quarteira (in the Algarve region), but originally from Afife, in the Minho region. The love for the warm and drier weather was enough to make him come from the top north to the top south of Portugal.


Gonçalo always wanted to be a vet but then, with a destiny twist, he ended up studying Forestry. Three years after finishing his forestry degree, he entered the ISCTE Business Management Master. Shortly after finishing his forestry degree, he started working at a Portuguese dealer for agriculture and irrigation and he learned a lot. “In fact, these lessons and the Business Management master were the base for my future entrepreneur life”, Gonçalo adds.


Back in 2013, with a friend business partner, Gonçalo started a company that represented NPI in Portugal and was the base for keag, which was officially born in 2019. Keag’s core business is to represent and distribute the best agricultural irrigation brands in the Portuguese market and abroad. One of these high-quality brands is NPI, with its top of the line water storage solutions.  

NPI International

Five years after working with NPI, and with 15 years of experience working with water storage, Gonçalo had the opportunity to assist NPI at an exhibition in Bangkok and that is when NPI International began to take form. Gonçalo explains: “since NPI’s presence in Portuguese and Spanish speaking countries was smaller than it should be, I gladly accepted the challenge of promoting and increasing NPI’s presence in these markets.”

To do that, we have created NPI International: a shared company between keag and NPI in the Netherlands, in 2021. NPI International aims to develop NPI’s solutions and visibility in the Portuguese and Spanish speaking countries, as well as to provide proximity assistance to the Portuguese and Spanish local markets. “NPI International is in its second year of activity and the results achieved so far are promising”, Gonçalo tells.


“Considering the Portuguese and Spanish markets I would say that the primary challenge lies in countering the perception that cheaper alternatives equate to superior quality. In our water storage solutions we never compromise on quality, and this is what has sustained our presence in the market for over 65 years!”

Header photo: Gonçalo is member of the Quarteira bike team. Whenever our colleague Arjen is in Portugal he joins this group of dedicated bikers. Keag and NPI International are proud sponsors of the Quarteira bike team!

All water tanks that you order now are manufactured from MagiZinc® steel. This offers direct benefits for you. How?


MagiZinc® is an innovative replacement for conventional galvanised steels, providing superior corrosion protection even in harsh environments. This MagiZinc® is a new alloy, equaling 600 gram galvanization. It is a zinc coating that incorporates a small fraction of magnesium and aluminium.

The advantages

  • Higher protection against red rust, white rust and edge rust – Magizinc® 310 is the equivalent to Z600
  • Greater scratch resistance; less likely to show dents and accidental damage
  • Thinner coating so fewer raw materials input make it more sustainable to produce
  • Available on water tanks and steel roofs


It is very suitable for indoor and outdoor water tanks. The application of MagiZinc® increases life expectancy of the water tanks, which will reduce maintenance or replacement costs.


Despite its superior protection, steel should be carefully stored in line with earlier guidances.

Let us introduce you the people behind our film and water storage solutions

Our powerhouse Nicole

Nicole started her carrier at NPI in our warehouse, where she easily outworked her male colleagues. She was a brilliant order picker but after a few years she needed a new challenge, which our production management was happy to give her. She joined our production team.

Initially, as first lady at our pond liner department where she processes mother rolls to neatly stacked pallets with sealed pond liner rolls. Now, she is a real allrounder: welding different films and getting to know the intricacies of our special products department. Here we manufacture 3D pond bags and we produce many different film products to measure. And don’t forget her highly valued role in the projects on location these days. Welding and assisting in all weathers!

Nicole is our powerhouse. Always optimistic, always with a can-do-attitude and no challenge is too big for her. Keep up your good work, Nicole!

Cold spring nights with temperatures subzero lead to exciting days for (fruit) growers. Overnight frost can cause significant damage to fruit blossoms, threathening the harvest of entire fruit orchards with failure. 

Irrigation techniques protecting against frost damage

The past years we have lined various excavated basins and silos for (fruit) nurseries at home and abroad. Irrigation techniques have been shown to be very effective in the protection of fruit, trees or crops from frost damage. The water sprayed on buds from water sprinkler systems, connected to the basin, forms a protective film around the plant.  It cools down the plant and it keeps the buds above its critical damage temperature.

Continuity is key

Important in this frost protection method is that permanent sprinkling with water must be maintainted as long as there is a risk of the plant freezing due to frost. If the sprinkling of water would be interrupted, the water film would freeze completely and the plant would freeze to death.

Read about a few of our frost protection systems in Serbia, Poland and the Netherlands.

Interested in our water storage solutions for frost protection? Contact us now!
Contact us

All about our newest liner: the chlorine resistant liner

Chlorine reacting to the tank liner

For many applications clean water storage is indispensable. Despite of the fact that the use of chlorine is not desired in the horticulture sector, chlorine is a common helping hand in keeping water storage systems clean, avoiding contamination and bacteria growth in water. Due to the aggressive and unpredictable nature of chlorine, it is hard to always use the correct levels of chlorine in water storage. For instance, every increase of 10 °C of the water will double the activity of chlorine. Especially when the water is already clean, chlorine searches substances to react with. Most of the times this is the tank liner.   

ENPEX CP liner

Together with leading raw material producers and processors NPI has developed a new type of liner material, specifically suitable for the storage of clean water with higher doses of chlorine. ENPEX CPL (Chlorine, Potable water liner) combines good mechanical strength and UV resistance with a maximum Cl absorption of 250 ppm. This is 10 times more than the current usual liners used for storing clean water.

Supervision and training

NPI is highly certified in processing the ENPEX CPL, and is able to provide supervision and training for its customers to make correct installations and or process the liner at location when necessary.


NPI delivers the ENPEX CPL as a standard in 0,75 mm and 1,00 mm. We can also supply 0,60 mm on project base.

Together with our high grade water tanks and our steel roofs we provide you with an optimal and durable solution for the storage and protection of your clean water!

Want to know more about our chlorine resistant liner?
Contact us

Ensuring the highest quality of water in all circumstances!

Protect your water

Fresh and clean water is the key to your business! For many applications, a reliable supply of clean water is indispensible. The water needs to meet drinking water standards and/or needs to be free of dirt, debris, contaminants and bacteria. UV light should be blocked to avoid the growth of algae.

When you are looking for the maximum protection of your water we recommend you to install our steel roof. Our galvanised steel roofs are the most reliable and robust covering systems on the market. The roof is designed for all weather circumstances and can withstand snow loads and strong winds. The roof prevents:

  • Dirt and debris entering the tanks. No external contamination.
  • Direct sunlight, significantly reducing the growth of algae.

Easy installation

The roof consists of lightweight, easy-to-handle panels that can be linked together to create a watertight roof. The steel roof is provided with two hatches as standard to allow access to the tank.

The advantages

  • Protects against any form of contamination
  • Prevents evaporation
  • Protects against all weather conditions
  • Easy to install
  • Saves on filtration and water treatment
Save on filtration and water treatment! Contact us for more information about the steel roofs.
Contact us

Let us introduce you the people behind our film and water storage solutions

From temporary job to production leader

Jerryt entered NPI in his late adolescent years, son of one of our fellow production employees. What started as a temporary job, soon grew into something serious. Jerryt became a highly valued, permanent member of our production team within no time. He learned quickly and with his precise way of working, he soon mastered all the work. And more! Jerryt has a strong sense for technology and he was put to work on the more specialised tasks, producing different kinds of custom-made film products for specific purposes and welding 3D pond bags.

For the past five years, Jerryt has been production manager. He manages the indoor and outdoor welding team and is first point of contact. He keeps an eye on continuity and improvement of the production processes and is an indispensable link between the office, management, the production team and planning. This loyal, always cheerful guy (okay, except for 9 AM) gets every day the best out of himself and out of his colleagues.

What he enjoys most is the diversity and to play a role in contributing to improving, both quality and quantity wise. To many more years of Jerryt at NPI!

Empty water tanks

When your water storage tank is empty, it absolutely needs to be secured. As written before, it is really important to have a proper foundation. Besides this, it is also very important to give good stability to the tank, especially in situations when there is no water in the tank. Wind can slightly move the tank, potentially causing damage to the liner or deforming the circular shape.

Tanks on concrete

In many occasions the tank base is excavated for approximately 40 cm deep, but also many water tanks are installed directly on the concrete base. When installed on concrete, we always use tank base brackets. These brackets are L-shaped and their job is to join the concrete bottom with the erected metal tank wall at a 90 degree angle, creating a whole lot of extra support.


When installing a water tank, always fill the tank first before attaching the tank base brackets to the concrete. This allows the tank to settle first.

Want to know more about base tank brackets? Contact us!

A cost effective, simpel but strong solution to cover your water tank

Your water tank is located outside and is year-round exposed to the elements. And thus, so is your stored water. Algae formation, evaporation, heatening of the water by UV radiation and dirt worsen the quality of your water and could eventually lead to malfunctioning of the irrigation system and plant loss. To maintain the quality of the stored water optimal it requires a cover that protects your water. 

Have you considered the ENPI-float?

  • Protects against algae, evaporation, dirt and UV radiation
  • Reduces heating of the water
  • Withstands wind
  • Easy to install
  • Excellent buoyancy
  • Easy to clean
  • Available in any size
  • Cost effective

A good all-rounder is the ENPI-float. Since it is available in any size it is also extremely suitable for water tanks with larger diameters. This smart and relatively new solution is made from polypropylene and it is covered with small, air-filled bubbles which give the cover a high degree of buoyancy.

The top layer of the cover is white, which reflects UV rays. This reduces heating of the water in areas with high levels of sunlight. Also in harsh climates the ENPI-float does a great job. Especially for larger tanks it can be a challenge to keep a covering system in place in bad weather. Due to the shape of the bubble, the ENPI-float creates a vacuum on the water so the cover sucks itself onto the water surface. When firmer anchoring is necessary; the ENPI-float can also be delivered with weighted bags for wind protection.

The ease of installation is great; centre poles or reinforcement rings are not necessary. Moreover, the product can be installed on empty or full silos. Installing an ENPI-float is a typical one man job.

Would you like more information about the ENPI-float?
Contact us