Water hardness

Water quality and water hardness varies all over Europe, from Country to Country and even from city to city, town to town. It is important to convert hard water into soft water to be able irrigate your plants with the best quality water possible.

What is hard water? Water that concentrates a high volume of dissolved mineral salts, especially calcium and magnesium. The hardness is measured in milligrams of calcium carbonate per liter (mg /l). Depending on the concentration of magnesium and calcium in the water, we can talk about four types of water:

  • Soft water (concentration of less than 150 mg / L of calcium carbonate)

  • Semi Soft water (concentration between 150-200 mg / L calcium carbonate)

  • Hard water (concentration between 200 and 400 mg / l of calcium carbonate)

  • Very hard water (concentration between 400 and 550 mg / l of calcium carbonate.

Hard water can produce problems in the plants, like limescale precipitated in the root stem. When this happens, the plant cannot absorb the necessary nutrients, so if you add doses of nutrient solutions to the plant, they won’t have any effect on it. Moreover, if you want to add nutrient solutions of calcium and magnesium, you have to be careful with hard water, because you can cause a Nutrient Lock out: high amounts of these minerals in water, together with added doses of nutrients, can BLOCK or saturate plants roots, prohibiting them from absorbing the added nutrients.

Depending where you live, the water you receive at home has different dissolved salt levels. Living near mountains, near the sea or big cities are factors that affect the water quality. For example, take a look to this map of the water hardness at British islands:

hardness water in british islands

London area has hard water, while Edinburgh appears as a soft water area. The most important thing is that wherever you live, you can improve the water quality, lower the EC level and change it into soft water. If you irrigate your plants with the best water quality, they will be healthier and faster growing. And this process is possible with RO systems.

Reverse osmosis (RO) to lower EC

A high amount of calcium and magnesium in the water we are using to irrigate can cause deficiencies in our plants. The only reliable way to remove dissolved salts in the water, or what is the same, lower the EC, is a Reverse Osmosis System.

What are the benefits of lower EC? First of all, you will get plants with healthier and stronger roots that absorb 100% of all the nutrients you add, avoiding dissolved mineral salt accumulation in the roots, such as limescale. You will guarantee more food for your plants, because when your water EC levels are low or even 0.0 (pure water) you can add the nutrients the plants really need, without worries about excess or lack of nutrients. Fertilizers you add will also be more effective, and ultimately, your plants will grow better and healthier, which means better results and therefore better quality and more profits.

GrowMax Water has designed a complete range of Reverse Osmosis Systems for hydroponics, starting at 20 L/h of pure water, and designed to minimize the waste water, with only (aprox.) a 2:1 (bad/good) ratio. All units include an installation kit for easy connection indoors or outdoor. These systems reduce up to 95% of dissolved salts in your water, lowering the EC in addition to removing chlorine.

Converting your hard water into pure water will provide your plants the quality water they deserve. Visit our website and take a look of the range of reverse osmosis systems, and discover which one best suits your needs irrigation.


Water pressure is important to know when installing a reverse osmosis System

The first thing we need to know when installing a reverse osmosis System is the inlet water pressure. 

All membrane manufacturers base their production calculations on 60 psi(4,3 kg/cm2) and advise in most cases a mínimum pressure neccesary of 40 psi (3kg/cm2) for the RO unit to function correctly.

Importance of a good strong inlet pressure

With a good strong inlet pressure, RO units will produce a good quantity and good quality water, while also sending less water to drain.

Without a correct water pressure (less than 40psi/3kg) Ro units will produce less water, worse quality and also send more water to draon.

4 kg/cm, the optimal pressure
4 kg/cm, the optimal pressure


For this reason, all Growmax Water Garden Reverse Osmosis Systems include a pre-pressure gauge, pre-installed after the sediment prefilter and before the green carbon block pre-filtre and in all cases, before the membrane.

How to obtain the best results with your RO unit

If after installing the RO unit you see the pressure gauge below the mínimum requirement (40psi/3kg), you shoould install a Growmax RO Pressure Pump Kit, to obtain best results for quantity and quality of water. This Pump kit will raise your inlet water pressure by 40psi/3kg. Above your corrent inlet watwer pressure.

GrowMax Water has two Pump Kits available, the first for the Power Grow and Maxquarium units, then also a HF (High Flow) Pump to be used with the higher producing Mega Grow unit.

Remember that good, strong water pressure is the key to an optimum functioning RO unit.

Spring has arrived, begin your outdoor crop

Spring is the best season for starting outdoor growing. In Spain, the weather starts to get warmer, cold nights decrease, increase daylight hours … factors that make this the best time to start growing outdoor. But what about the water quality you will use to irrigate?

Often in the preparation of appropriate tools for cultivation, we forget the importance and quality of a fundamental element: water. This element is the basis for growth, and although weather conditions are now more favorable for growing, without a filtration system that gives good quality water, plants do not proliferate as we would like. Because water isn’t equal everywhere…

EC control levels and chlorine

For example, high amount of minerals, a high EC, or heavy metals in water can block the absorption of nutrients needed by the roots. If this situation happens, no matter the quality of the nutrients that you use for plants, because due to the high concentration of mineral salts and calcium in the water, they won’t absorb it. As a result, our plants will show deficiencies.

On the other hand, during the warmer months, municipalities add more chlorine to the water networks to prevent the spread of viruses and bacteria. During this time, the water contains more chlorine, which burn before the roots and removes the beneficial bacteria of fertilizers.

To prevent these problems and to ensure the quality of water, there are water filtration systems, which eliminate up to 99% chlorine. If water in your area is very hard, and has a high EC, with RO systems  you will eliminate up to 95% of salts and heavy metals, and up to 99% chlorine. In this way, you will add the necessary nutrients that your plants really need, and they will grow healthier.

So remember, if you’re going to start outdoor cultivation with the arrival of spring time, consider the quality of the water you’re going to irrigate. Using filtration systems or RO can help you get the best results.


There are several reasons to lower the EC and eliminate chlorine from your water. If your plants could talk, they would ask you for quality water, and we explain you why.

eliminate chlorine and lower the EC


Keep in mind that our plants can receive an EC of up to 1,4 to 2,2, according to the type of plant or growing stage. If, for example, the water we use has an EC of 1,0 then we will ONLY be able to add from 0,4 to 1,2 of nutrients to reach our maximum levels. If on the other hand, we start with an EC in the water of only 0,1 or 0,2 or even an EC of 0,0 then we will be able to add much more nutrients to our plants.


By lowering our EC we eliminate salts that we don’t want in our water. This will give us healthier roots, by avoiding lime scale build up in the roots and they will be able to absorb 100% of the added nutrients.


We know that soils contain Beneficial Microorganisms whose function is to protect plants roots, by keeping them clean and healthy, so that they have maximum ability to absorb nutrients and fertilizers. However, when we water our plants with chlorinated tap water, the chlorine, a chemical, kills off our beneficial bacteria that is present in the soil. Chlorine will also burn our plants delicate uptake roots.



By using a garden reverse osmosis system to lower your water’s EC, we achieve a balanced pH, as RO water has a pH of approximately 6,5.



A high EC may contain larger quantities of hard water minerals, like calcium and magnesium, also known as limescale. High amounts of these minerals, together with added doses of nutrients, can BLOCK or saturate plants roots, prohibiting them from absorbing the added nutrients, which is also known as “nutrient lock out”.



In the case that we have to use specialized microorganisms (for example to kill worms or other parasites, etc.), it will not make sense if we water with chlorinated water, because the chlorine will kill these microorganisms that we have just purchased.



Many times we encounter small problems or challenges with our plants and gardens, without knowing where some of these problems come from (yellow, dry leaves, burnt tips, stunted growth, etc). Professional growers assure us that if we begin growing by using a low EC water, many of these problems can be avoided, as we will know EXACTLY which nutrients and what quantities our plants are receiving.



By starting with PURE WATER, our plants will not absorb any undesirable elements that can be present in the water and therefore we will achieve a 100% effectiveness out of our added nutrients and fertilizers.



Just as a house must be built with a good, strong foundation, you must also start with PURE WATER to have a strong foundation for GROWTH. Knowing that we start with a clean, chlorine free, low EC water, is the right way to help our plants to GROW TO THEIR FULL POTENTIAL!



Finally, one simple question. If for our own personal drinking water we prefer a clean, quality, and chlorine free water (often bottled), why wouldn’t we give the same water to our plants? They also DESERVE QUALITY WATER!


What is hard water? Hard water is that which has a high concentration of the mineral salts calcium and magnesium, also called “limescale”. The formation of limescale is a problem for our plants and our plants roots.Calcium phosphate is what our bones are made of and it is 95% water insoluble. The calcium phosphate often falls out of the nutrient solution as lime scale. Once lime scale is formed both the calcium and phosphorus become unavailable to the plant.

We can use our EC meter to measure the total quantity of dissolved mineral salts in our water but that still will not tell us what percentage of those salts are hard water minerals. 

 To compensate for excess minerals, hard water nutrient formulas are usually lower in calcium and magnesium, with reduced levels of sulfates, so a hard water nutrient formula complements the minerals already present in the water. 

Also, if water is excessively hard, or an analysis shows  toxic levels of trace elements such as sodium or boron, the water should be filtered or processed.

HOWEVER, most growers will simplify water quality management by using only reverse osmosis water. RO removes all (90-95%) of the mineral ions, so the grower starts with clean, pure water. Therefore, if you use RO water all of the essential elements will come from your nutrient solution, not from the source water, creating the perfect mineral balance for plant growth. 

RO is definitely recommended for any applications where a water softener is in place. A water softener does not remove the calcium and magnesium from the hard water, rather is replaces them with sodium ions, often at toxic levels. If sodium exceeds 50ppm the plants may not be able to reach their true genetic potential. 

RO water is also perfect for topping off your reservoir between nutrient changes, replacing water lost to evaporation without adding any unwanted minerals.

Experts say that if an analysis shows that even one element is approaching toxic levels an RO system is definitely needed. 



All municipal water supplies contain chlorine, a chemical disinfectant used to kill off deadly bacteria and virus in the water supply. This chemical in turn, can directly attack our plants and gardens. We know that chlorine is present in our drinking water because we can smell and taste it’s presence, many times making it undrinkable. So the question is: If we don’t want to drink the water from the tap, why do we want to give it to our plants?

Now, more than ever, in the summertime, with the high temperatures the local water companies add extra high doses of chlorine to the water supply to combat the bacteria and virus that can be present.

Let’s talk about how chlorine can affect our plants. We know that our soils contain beneficial bacteria whose function is to protect the plants roots, so they will be stronger and healthier and of course have maximum capacity to absorb the nutrients and fertilizers that we give to our plants. However if we give chlorinated tap water to our plants, the chlorine can kill off the beneficial bacteria present in the soil. This same chlorine, a chemical contaminant, will burn your plants delicate uptake roots, again preventing maximum absorption of needed nutrients.                                                                                                          If we are also purchasing these beneficial bacterias to add to our soils then of course it makes no sense to give our plants chlorinated water. 

The best way to ELIMINATE chlorine is to filter it thru a quality activated carbon or better yet an activated carbon block filter. Carbon filters will also reduce or eliminate other chemical contaminants, such as Gases, Oils, Pesticides and most other Volatile Organic Contaminants (VOC’s).

In answer to the initial question, we definitely do NOT want to water our plants and gardens with chlorinated tap water!


1--ECO-GROW Garden Grow Super GrowPro Grow 



When to use RO water and Why Growers prefer pure water

Many growers worldwide already know of Reverse Osmosis (RO) and the need to achieve pure, contaminant free water for their plants. Whether using soilless, hydroponic systems or traditional gardening with soil, the water we use for our plants is a very important part of growing.

We know that Chlorine can burn our plants roots and also can kill off the beneficial microorganisms present in our soils. Chlorine can be eliminated by using a Activated Carbon Block based FILTER UNIT.

However, a high EC can also be a problem. EC is the measurement of the Dissolved Solids or the dissolved Mineral Content in your water. Too much calcium and magnesium in your water can cause Nutrient Lock Out – where the plants roots are blocked from absorbing necessary nutrients. Other dissolved contaminants; Lead, Cadmium, Boron, Arsenic and other heavy metals can also be toxic for your plants (just like in the human body).

The only way to eliminate Dissolved Solids and lower your EC is with a Reverse Osmosis system. GrowMax Water has engineered a full range of Garden Reverse Osmosis systems, designed with High Flow rates for Growers and easy to install connections for indoor or outdoor installation. GrowMax RO systems will reduce up to 95% of dissolved solids in your water, lowering your EC as well as eliminating your chlorine. This pure water will give you a perfect starting point when you mix and add your essential nutrients for your plants.





When to use Filtration Systems?

We all know that using quality water is important for cultivating and growing our gardens. But all water is not the same quality to begin with. Some water has high EC, some have high iron and manganese content, some well waters are even contaminated with bacteria. However ALL municipal city water does contain chlorine.

Chlorine is a chemical used by cities to kill off possible bacteria in the water and assure that the water is potable or safe to drink. However, as chlorine is a chemical it should then be removed, before drinking. 

The same is true for your plants and gardens. Chlorine is a chemical that must be removed or it will kill the beneficial bacteria present in your soils and also burn your plants uptake roots, limiting the absorption of vital nutrients and essentially slowing your plants growth. 

You do not drink water from your swimming pool nor do you water your plants and gardens with swimming pool water. Chlorine should most definitely be removed from your garden water!

If the EC content of your water is reasonably low and there are no other major contaminant problems with your water, then a FILTER unit is a simple, economical solution for your to eliminate chlorine, a chemical contaminant, from your garden water.

See here the GrowMax Water Filter Line with their high capacity GREEN CARBON BLOCK FILTERS, which will eliminate up to 99.99% of the chlorine present in your water.


Here we show you an installation of a SUPER GROW 800 L/h at a strawberry farm. Healthier plants and tastier fruit!

IMG_20140519_192818_Italy Green house strawberries with Autopot Systems Italy