Hydroponic Water – Everything You Need To Know

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By Emily Cooper

Utilizing hydroponics for your garden means substituting water for your usual potting and garden bed mix. If you’re looking for a method of horticulture that allows for easy nutrient delivery, saves water, and, when done correctly, produces a larger yield, then this is for you.

On our website, we’ve covered the many kinds of crops you can grow in hydroponic units, which vary from bell peppers to cucumbers, onions, and more.

While there are many ways to grow hydroponically, each method has its own pros and cons. The one thing they have in common is they all operate with water or a nutrient solution.

The go-to type of water to use is distilled water because it contains no harmful contaminants. You can also use distilled water to dilute tap water, which in certain areas can be challenging to work with because it has a lot of minerals that can eventually cause a build-up.

We’d also suggest using captured rainwater or tap water undergoing reverse osmosis filtration.

For those who are new to hydroponics, here are the basic setups to understand.

Basic Hydroponic Setups

With any hydroponic setup, you will need light (natural or artificial), carbon dioxide (just well-ventilated air for roots), and oxygen (again for the roots). All you’re doing with hydroponics is replacing the need for soil.

Soil holds the nutrients, water, and minerals for the plant to tap into and feed on. Soil also helps to hold the plant in position – and in a hydroponic system, this is replaced with an alternative growing medium.

The basic hydroponic setups that most growers will talk about are:

Water Culture

Considered the simplest setup, a water culture is created by soaking the plant’s roots in water, with the plant firmly held in place via some sort of growing medium. The nutrients are in the water, with an air pump allowing the roots to absorb them.

Wick System

A wick system is considered a very basic hydroponic system with the plants drawing water from the reservoir via a string into the growing medium.

This is, in fact, a very useful technique for gardeners who are leaving for a few days and need to water their indoor plants.

Nutrient Film Technique

Usually referred to as NFT, this hydroponics method has the plant potted in net pots, with the roots suspended above a constant flow of nutrients and water.

The flowing water generates bubbles, which aerate the nutrient solution.

Ebb and Flow

Like the NFT setup, the plants are potted in net pots with the roots suspended. But rather than constantly flowing water, this system works by periodically flooding the plant-holding area and wetting the roots when required.

Selecting a growing medium that absorbs and retains the water is critical.

Drip Irrigation System

As the name indicates this requires water drippers to feed your plant’s roots. The water solution contains the nutrients that the plant needs, and usually, this is a closed circuit, with the excess water flowing into a reservoir.

This method is used for larger plants and trees.


This is a technique that promises to deliver outstanding results. But this being said, it is for advanced growers.

With aeroponics, the water is vaporized via sprinklers. By doing this, you’re creating a perfect aeration of nutrients, which is absorbed into the plant’s system very quickly.

While this is a great system, be warned that the sprayers can get clogged.

Now, back to the question at hand, hydroponic water.

What Type of Water Should You Use in Your Hydroponic System?

While watering the garden with tap water is fine, the quality of the water matters when it comes to hydroponics. This is down to the extent of filtration or the water quality from the reservoir or source.

All these variables will affect the chemicals, minerals, and bacteria in the water. This being said, there are a number of methods you can always treat water to ensure that these extra elements are removed.

Treating Water For Hydroponics

When treating water for your hydroponics system, you want to ensure that you’ve removed all impurities, excess minerals, and bacteria.

To remove chlorine, place the water in direct sunlight. The UV rays will do the work naturally over the course of two days. If you’re looking at keeping bacteria to a minimum, you will want to use a UV light.

In larger cities with bacteria issues, water companies will use chloramine. You can use chloramine tablets to remove it from your water supply. These tablets will also remove chlorine.

If you don’t have access to these tablets, you can run the water through a charcoal filter.

As mentioned, if the water from your taps is hard, you can use reverse osmosis to remove excess minerals like calcium and magnesium. While not bad for the plant, these minerals can build up over time, causing issues.

The last measure you can take to ensure the water is filtered correctly is running it through a debris filter.

Once these steps have been taken, your water should be ready for your hydroponic system.

So, what other frequently asked questions (FAQ) are made about hydroponic water?

FAQ About Hydroponic Water?

As you can imagine, there are a million and one questions budding hydroponic gardeners have about the hydroponic water they’ll be using in their systems.

But we will answer the most frequently asked questions typed into Google.

Is Distilled Water The Best For Hydroponics?

The simple answer is – yes. Distilled water has had all the harmful chemicals and excess minerals removed. That means when you add nutrients into your system, you know there’s nothing counteracting the chemical balance.

How is Rainwater in a Hydroponics System?

Rainwater is great, but be aware of how the water is collected. If your roof and gutter’s surface is made from heavy metals or asbestos, you might want to treat the water before putting it into your system. This being said, if you don’t have that kind of roof or gutters, the water should be perfect for hydroponic systems.

Unless your area experiences acid rain…

Could I Use Well Water for Hydroponic Systems?

Again there are many variables at work, but some well points can be heavy in minerals. This, in turn, makes it unsuitable for hydroponic systems.

If treated properly, or if your well point is fed by a clean spring, then there’s no reason not to use it.

Purified Water For Hydroponics?

If the water is treated with a purification process, it should be perfect for any system. We’d highly recommend using purified water.

Now that we’ve answered a few questions, let’s dive into making our own nutrient water for hydroponics.

Start Making Your Own Nutrients for Your Hydroponic System

For most, the biggest concern with starting a hydroponic system is how to feed the plants. While there are many solutions, we’d recommend starting with store-bought and formulated solutions.

We’ve spoken about the best nutrient suppliers in the game, so it’s up to you to decide which one suits your needs the best.

These products will have instructions about how to use them. But, one tip they won’t include is adding Epsom salts. The scientific name for this household mineral is Magnesium Sulfate, which is fantastic for plants.

The list of benefits is long, so always have Epsom salts on hand.

For those looking at adding worm tea, or any other natural fertilizer, you will need to ensure that they don’t affect the pH of the water, which is one of the most essential jobs for maintaining a healthy hydroponic system.

But what is the correct level?

What is The Correct pH Level for Hydroponics?

The pH level of your water is vital for the health of your plants in the system. While generally, you want the pH of the water to be a little more acidic at around 4.0 to 5.0, this can vary with certain crops.

Cucumbers want their water between 5.0 – 6.0 pH. And as another rule of thumb, veggies like a higher pH of between 5.5 to 6.0, while berries will want lower levels of around 4.0 – 5.0 pH.

Make sure you do some reading before adjusting the levels.

Now, let’s talk about adjusting these levels.

Adjusting the pH Levels in Hydroponics

It may seem intimidating, but you can adjust the pH levels of your hydroponic system with relative ease.

There are loads of professional products on the market that will give you step-by-step instructions. But adjusting pH levels can be done naturally.

If you’re looking at lowering the pH levels, substances like baking powder will help.

When raising the acidity, squeeze a lemon into the mix or vinegar. Remember, if you are doing it with household products, monitor the levels carefully and only make minor adjustments.

Now that we understand how to adjust the pH of your water, let’s talk about the best methods of circulating and aerating it.

How to Aerate and Circulate Water In Hydroponics

In most hydroponic systems, you need a hydroponic air pump to either aerate or circulate the water. You can have multiple different types of pumps in the system, ensuring that nutrients are absorbed or circulated.

The most common pump utilized in hydroponic systems is a submersible pump. This being said, there are two pump systems that will move water:

  • Submersible water pumps operate in the water and move the water via a pipe.
  • An inline water pump is a pump that moves water from the source, which is outside the system, and back into it.

Most growers will settle with a submersible water pump as they are the easiest to find and are pretty easy to maintain.

Submersible pumps are also easier to install. While an inline water pump will offer more power for more extensive circulation, a submersible pump will be OK if your system is for home use.

Also, if you have an aeroponic or ebb and flow system, it’s in your best interest to invest in a timer.

While you might be good at remembering tasks, the fact is these systems will work better with a timer that will switch the pump on and off every 20-40 minutes throughout the day.

If you think your plants need more aeration or you are working with a deep water culture, you will have to use an air pump. Getting the correct amount of oxygen into the water will also help prevent diseases and algae.

When a system does start to produce algae, it might be time to change the water. But how often should a grower change their water?

When Should Growers Change Their Hydroponic Water?

The typical home hydroponic system can do with a water change every two to three weeks. If water levels drop, you can top up with the system supply.

However, this schedule can change for several reasons, but it will most probably be from too much algae. You should change the water immediately when a system starts to develop major issues, like abnormal algae growth.

While a small amount of algae is alright, too much will create an environment perfect for breeding bacteria, which will harm your plants.

Another reason for changing the water is if the pH levels are completely unfixable. But just a reminder, when changing the water, make sure to clean the system’s surfaces with a plant-friendly substance.

But what if you want to recycle hydroponic water? Can you?

Can you Recycle Hydroponic Water?

The simple answer again is yes; you can, in fact, reuse hydroponic water. If you do want to use water in your garden, it is recommended to dilute the water with regular tap water.

This water can also be poured down the drain, but it is excellent for general garden use because of the nutrients in the water. However, if you have allowed it to become very acidic, make sure to test the pH of the water first. The neutral pH of water is around 6-7, so change the levels accordingly.

And if you are checking for EC levels, ensure the reading is close to 0 as possible before disposing of it. You can also put the water through a reverse osmosis filter, UV disinfection, or pasteurization setup.

Make sure that you can dispose of the water quickly, as if it is left lying around, it can become a breeding ground for pests. We’d strongly recommend having a schedule in place where changing water aligns with watering timings in the garden.

One of the main reasons why hydroponic water will turn is down to poor temperature. But how do you maintain water temperature?

How to Regulate Water Temperatures in Hydroponic Systems

Temperature control is key to your plants’ health in the hydroponic system. Huge temperature fluctuations can cause plant shock, stunting the roots’ growth.

Ensure you can monitor your system’s temperature and maintain it between 65F and 80F. When a plant’s roots are exposed to harsh temperatures, they can die off, resulting in dead plants.

To ensure your system doesn’t experience significant temperature changes, you should set it up in a shaded area. Direct sunlight on the system will heat up the water flowing through it.

Another point in the system is the reservoirs; these should also be placed out of direct sunlight. To lower the temperature more, you can bury the reservoirs or paint them.

Water chillers will also help, especially for crops that require colder temperatures. Check out our top recommendations: Best Hydroponic Water Chiller

Other methods include covering the system with a shade cloth, painting the system, or investing in a larger reservoir.

Managing water temperature will save you time and money, and it is the easiest aspect to manage.

Another element that will help with temperature control is topping the system’s water.

So, what is the perfect water level to maintain?

Managing Hydroponic Water Levels

Water levels vary between systems. But generally, your hydroponic system’s water level should keep your plant roots wet while your plants’ stems should always be kept dry.

Ebb and flow systems should have a water level of around two inches below the growing medium. This will ensure that the roots are never exposed to too much air.

In deep water culture setups, the water level should be around one inch below the net pot. But if the bottom of the plant becomes too dry, you will want to raise the water levels. Be aware of not over-adjusting and creating a soggy root area leading to root rot.

With systems like NFT, aeroponics, wick, and drip, there are no suggested levels as these deliver water in a different method.

Overwatering can occur in hydroponics and can be caused by,

  • Water levels are too high, with the growing medium being oversaturated
  • Not enough drainage in the system
  • Water flooding the growing medium pots
  • And water pump or timer malfunctions

Generally, when overwatering does occur, simply giving the plants time to dry out is the best solution.

Complete Guide About Hydroponic Water

It’s always important to remember that when building a hydroponic system, you are, in effect, creating a microenvironment.

Everything needs to work together for the plants to thrive, so all elements are essential. And when something does go wrong, a chain of events occurs. You can easily adjust and fix the problem by working backward when troubleshooting.

And if you need to read up about hydroponic water issues, you can always reread this article.