The Surprising Reason Your Aquarium Plants Aren't Growth

Have you ever wondered why your aquarium plants won't grow - no matter how much light or fertilizer you provide? It turns out a secret ingredient may make or break your plant growth. The secret to unlocking your aquarium's full potential is water parameters. 

The water you use to fill your tanks could be the culprit, holding back your plant's growth. There are four factors that influence how well plants can grow. pH, HG, KH, and water flow.


pH measures how acidic or basic a solution is, and it is based on the concentration of hydrogen ions in the solution. In general, a suitable pH range for most aquatic plants is 6.5 and 6.8. If the pH is too high or too low, it can limit the availability of specific nutrients that plants need to grow, such as iron and manganese.

Additionally, pH levels can affect the concentration of dissolved CO2 in the water. With low pH, water has a higher concentration of dissolved CO2. This is why soil lowers the pH to around 6.5—to create a favorable environment for plant growth. 


General Hardness (GH) refers to the water's dissolved calcium and magnesium concentration. These minerals are essential for building cell walls and supporting other plant biological processes. However, GH should not be used as a direct test for calcium and magnesium. 

You can have higher calcium and low magnesium and still get a high GH reading. This is why GH is not too important, but it is something to consider due to livestock.


Carbonate hardness is what matters between the two. KH measures carbonate and bicarbonate ions in the water and plays a significant role in maintaining pH levels. 

The ideal KH levels for plants are between 3 and 8 dKH. Going any lower can result in wild pH swings, while higher levels can lead to difficulty controlling the pH, potentially harming fish and plants. Substratum, hardscape, and driftwood can impact this. 

Therefore, your local water must be tested to create the best plant-growth environment. 

Water flow 

Water flow plays a crucial role in plant growth. Flow also helps prevent algae growth in the plants. However, it can also lead to surface agitation, resulting in a loss of CO2 - a crucial factor in maintaining healthy plant growth. 

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