Skip to Content

How Often Should You Change Water For Hydroponics? (Best Practices And Tips)

Hydroponics is a unique invention that allows you to get fresh vegetables anywhere, even if there is no access to sunlight. However, such a device requires constant maintenance and that is what we will talk about here.

Change the water in hydroponics every 2 weeks. For larger systems, water changes may be less frequent, but for small hydroponic gardens, you may need to change the water every week. When changing the water, be sure to clean the unit and adjust the pH of the fresh water.

This is a short guide on how to change the water in a hydroponic system and I will go into more detail further in this article.

smart garden 3

Why you should change water for hydroponics?

The first advantage of changing the water in a hydroponic system is that the plants will grow in sterile conditions and not get sick. If you don’t change the water for a while, pathogens can multiply in very large numbers and lead to root rot.

It is almost impossible or very difficult to save a plant affected by root rot. As a result, you will have to start all over again.

The second reason to change the water is to control the water pH and trace elements. As plants grow, they release various substances into the water that change both the water pH and the mineral composition of the water. This can cause the plants not to grow properly.

And third is biofilms. These microorganisms cling to the walls of the hydroponic system inside the tank and to the roots of the plants. Over time, they will become very abundant and they will reduce the flow of water in the system by blocking the pipes. Also the nutrient distribution will deteriorate and the plants will suffer from nutrient deficiencies.

Read also: How to choose the right hydroponics?

How do I change the water in my hydroponic system?

Changing the water in hydroponics is not difficult, but it takes a little time. In addition, there are two types of water changes, so let’s talk about this in more detail.

Water refilling

The first kind of water change is a topping up. During growth, the plants take in water to create new cells and for evaporation by the leaves. As a result, you have to constantly refill the tank.

You need to do this about every 2 to 3 days. It depends on the size of the system and the number of plants. You need to constantly monitor the water level in the tank and top up if it drops.

This way the water is slowly replaced. The plants remove water from the tank and you are constantly refilling with fresh water.

Full water change

You also need to change the water completely to remove all pathogens and other substances that negatively affect plant growth. You should do this about twice a month. For larger systems you can change the water a bit less frequently (every 20 days) whereas for smaller systems a bit more frequently (every 10 days).

However, you should not stick to any rules unconditionally. It is best to constantly monitor the water quality (color, odor, pH level). Also inspect the roots of the plants from time to time. As soon as you see something wrong it’s time to change the water.

To change the water in your hydroponics system first of all de-energize the whole system. This is very important because otherwise you put yourself at unnecessary risk.

Next, pull all the plants out of the system and place them carefully on a tray so that the water does not spill around the room.

If your system is small, pour the water down the toilet or outside. Use a pump to remove water from a large system.

Clean your hydroponic system

Before pouring new water into the system you need to clean it. Pour some water into the tank and use a brush to clean all the walls and other elements of slime and biofilm.

For small hydroponics, you can use a toothbrush. Remove all dirt from the tubes to improve their flow capacity. You can wash the air stones in the sink under running water.

Pour out all dirty water from the tank and rinse it with clean water. Next, fill the entire system with water but do not put the plants in their places.

Pour 35% hydrogen peroxide into the tank. Use rubber gloves to avoid skin damage. Add 3 milliliters of hydrogen peroxide to each gallon of water.

Turn on the system for about half an hour to give it a good clean. It is important that all the elements of the system are in place and that the solution cleans them.

Next, drain the system and rinse to remove any residual hydrogen peroxide solution. That’s it, you’re ready to fill it with fresh water.

What water to use?

The best water for hydroponics is distilled water. If you use such water, it will stay clean for a longer time.

However, the disadvantage of distilled water is its cost. This is especially noticeable if the hydroponic system is large.

You can also use regular tap water for your hydroponics system. It is well suited for this purpose and there is usually no difficulty. This will allow you to save money.

The disadvantage of tap water is that it contains chlorine. But the chlorine content is usually small and will not harm your plants. Also, you can leave it for one day and all the chlorine will go away.

Adjust water pH

Before you fill the tank with water, you need to check its pH level. This is actually a very important indicator because if it is not correct, the plants will grow very poorly or die altogether.

For most hydroponic plants the optimal pH is 5.5-6.0. This is how they are able to take up all the nutrients you give them. The result is a bountiful harvest.

To measure pH, buy a tester that is designed for this purpose. There are plenty of good testers on the market now and you will have plenty to choose from.

Use water adjusters to change the pH. These products are available both online and at any hydroponic store.

Add fresh nutrients

Also, don’t forget to add fertilizer to the fresh water. Use the fertilizer you used before you changed the water.

This is important because plants do not like sudden changes and a different fertilizer can be detrimental to them. Do not use too much fertilizer as it can burn the roots.

That’s it, now you can put the plants in their places and expect a bountiful harvest.