Hydroponics pH Keeps Rising: 3 Possible Reasons & Easy Fixes

Setting up a hydroponic tank is very fulfilling, but before you can enjoy the results, you must ensure the right growing conditions for your plants. To that end, having a balanced pH level is essential.

In the absence of a balanced pH level, your hydroponic plants will not be able to absorb the required nutrients for their growth.  A higher pH level can lead to discoloration of your hydroponic plants and also cause their death due to nutrient deficiency. 

That’s why it becomes crucial to learn what to do if your hydroponics pH keeps rising. I am going to explain all the possible reasons behind it along with their dedicated fixes to help you all to deal with this condition effectively.

Thankfully there are ways to increase and decrease the pH level in your hydroponic system to keep your plants healthy. 

hydroponics ph keeps rising
Hydroponics ph keeps rising

What is pH?

PH level measures the acidic level of water. It calculates the amount of free hydrogen and hydroxyl in water.  The range is between 0 to 14 and 7 is neutral. If the pH level of water is less than 7 it denotes acidity.

However, the range above 7 stands for base. The right pH balance is crucial for your hydroponic system as it impacts the nutrient availability of the plants.

If the pH level is too high or too low the plants will not be able to absorb the right amount of nutrients and suffer from deficiency.

Ideally, the pH range for hydroponics should be between 5.5 to 6. 

What is pH
What is pH?

Why pH is Important in Hydroponic Systems? 

The plant roots in a hydroponic system draw nutrients mixed in the water. The nutrients originally are created from organic and inorganic compounds in the soil and the bedrock. Microorganisms play a major role in keeping the soil substrate fertile while the minerals and water buffers control the pH levels.

Why pH is Important in Hydroponic Systems
Why pH is Important in Hydroponic Systems?

The plants in this system are adapted to a controlled pH environment. Since there are no nutrient cycles within the soil it’s the responsibility of the hydroponic growers for recreating the ideal environment for the plants to grow absorbing the right ingredients. 

 No matter which hydroponic system you are using the goal is to provide the right nutrients to the plant roots depending on the plant type while maintaining the pH level of the water to ensure adequate nutrient absorption.

In the absence of a proper pH level, your plants will starve even though there might be sufficient nutrients in the water. 

Hydroponics pH Keeps Rising (Possible Reasons) 

The pH level of your hydroponic system can increase for many reasons. The most common reason is hard or untreated water. Such water contains several nutrients and can lead to higher pH levels. Mixing hard water with other nutrients increases the pH levels further. 

The pH level might also increase when the plant roots absorb the nutrients. Additionally, the temperature of the tank also affects the pH levels. Carbon dioxide and oxygen are water soluble and carbon dioxide forms carbonic bonds in water. 

Hydroponics pH Keeps Rising (Possible Reasons) 
Hydroponics pH Keeps Rising (Possible Reasons) 

As the tank temperature increases due to high temperature and air pumping the carbonic acids become carbon dioxide and evaporate out of the water. Besides these, there are a few other reasons that cause the pH level to raise. 

Nutrients availability

The plant nutrients in the hydroponic system are more acidic. As the plants absorb these nutrients the acidity is removed from the water and the pH level rises or drops. 

Strength of nutrient solution

The strength of the nutrient solution also affects the pH level of the water. If the plant does not have sufficient nutrients, it’s going to absorb more nutrients which will cause the pH level to rise.

Growing medium

The growing medium you select for your hydroponic system also affects your pH. For example, Coco coir as a growing medium goes through changes during the crop’s life cycle which affects the pH level of the tank. 

How to Keep the Right pH Levels?

The success of your hydroponic system depends on the balanced pH level it has. In the absence of a proper pH level, the plant roots will not be able to consume the required amount of nutrients and will eventually die.

However, since the pH level changes due to many reasons, it’s essential to be prepared for handling such a situation.

The first step for maintaining the ideal pH level in your hydroponic tank is testing. Thankfully a variety of testing kits are available for this purpose. You can opt for test strips or liquid tests as they are the least expensive options and are available at local pool stores. 

How to Keep the Right pH Levels
How to Keep the Right pH Levels?

The pH level depends on the type of system you have. For those using a recirculating system, it’s best to adjust the pH levels as per the test results of the supply manager.

For media-based systems, however, the pH level changes as the nutrient level travel from the supply reservoir to the growing base. Depending on what the results might turn up, you have to either increase or lower the pH level to reach a balanced stage.

Lowering pH levels

If your pH level is too high, use the following steps to lower it. Get a pH-down product. Test the pH of the nutrient solution by following the given instructions. If the pH is high add a small amount of the “pH down” product and stir it with a spoon Use the pH-down solution in a small amount to avoid overdose.

Check the pH level again in an hour. If the pH level does not go down repeat the above process once more You can also use muriatic or sulphuric acid to lower the pH levels 

Raising the pH leve

The most popular method for increasing the pH level is the Dyna-Gro product or PH-UP. PH-UP is a liquid plant supplement that is added to the hydroponic system to increase pH levels. However, it’s only advisable to use this solution when the pH level falls lower than 5.5.

Since it’s a potassium solution, PH-UP increases the pH levels. If you are not interested in using commercial solutions to increase the pH levels, you can also use baking soda. Though baking soda brings the pH level to a balanced point, the sodium compounds in baking soda stop the plants from absorbing the calcium they require.

Frequently Asked Questions (FAQs)

Can we naturally lower pH in hydroponics? 

Yes, there are ways to naturally reduce the pH level in hydroponics using lime and baking soda. Lime increases the number of hydronium ions and reduces the level of hydroxide ions thereby reducing the pH level in the water.

Does aerating water raise pH in hydroponics?

The nutrient solution needs to be aerated continuously. When the water is aerated the chemical concentration changes and affects the pH level. As the CO2 escapes, the pH level goes up.

How often should I adjust the pH hydroponics?

As beginners, it’s best to check and measure the pH level daily to get a hang of the system. Eventually checking it every 2-3 days is advisable. 


By following the steps mentioned above you will be able to keep your hydroponics happy and blooming. Remember the key to a blossoming hydroponic system is a balanced pH level. 

Leave a Comment

Your email address will not be published. Required fields are marked *

Scroll to Top