How To Raise KH In Freshwater Aquariums

How To Raise KH In Freshwater Aquariums

In this article, we will discuss how to raise KH in freshwater aquariums. KH is a measurement of carbonate hardness which is one of the factors in the underwater ecosystem that will have an impact on the overall health of your fish, as well as the aquatic plants in the aquarium. Keeping your water chemistry balanced is one of the most important things you can do with an aquarium.

What is KH?

Before you can understand how to raise KH in freshwater aquariums, you should first understand what it is. KH stands for “carbonate hardness, and it stands for the water hardness in the aquarium. Normally, you can express carbonate hardness in degrees known as dKH.

Why Worry About KH?

This is where things can get a bit confusing! dKh (carbonate hardness) has a direct relationship with KH (alkalinity level) in your aquarium. A higher KH level will equate to a more stable pH level which will prevent pH crashes.

A low KH level will make pH fluctuate greater and allow more rapid pH movements. When the KH measurement is under 2-3dKH (35.7-53.6ppm), the night time respiration of the plants or animals can create large pH downshifts (due to CO2 production) which harm and eventually kill aquatic animals. This is known as pH shock and it is due to lack of KH, otherwise called water buffering.

How to Raise KH Levels

When it comes to raising the Kh levels in your aquarium, you have several different strategies of which we will discuss the pros and cons of each.

Baking Soda

Baking soda is something you should easily be able to find in your home. How much baking soda you should use in the aquarium will depend on how big the aquarium is. For example, you might add one teaspoon of baking soda to a tank with 50 liters. This will raise the dKH by 4 dKH.

However, it’s important to note that you shouldn’t put too much in at once to raise the KH levels because this sudden drastic change can be deadly for your fish.

Because baking soda consists of alkaline, this will also raise the pH level, which can be bad. You also have to exercise caution to make sure that you buy baking soda rather than baking powder—there’s a difference.

Professionals Buffers – SeaChem Alkaline Buffer

Seachem Alkaline Buffer is a phosphate-free sodium bicarbonate-based buffer which makes it better suited for aquariums with plants and a higher algae risk. The advantage of using the SeaChem Alkaline Buffer is that it raises the pH along with the alkalinity (KH) of your aquarium water and keeps it at an acceptable range between 7.2 and 8.5 which is an ideal for freshwater aquariums.

Important to note, buffers like this have been designed for water that is very hard. As with adding any chemical to your tank, adding too much can be harmful to your fish so only add the recommended amount for your size aquarium.

CO2 Systems

If you are constantly having problems with the KH levels in your aquarium, you may want to invest in an aquarium co2 system. Planted tanks rely on CO2 and light to create food through the process called photosynthesis.

However, higher CO2 levels can cause KH and pH levels to fall and also deprive your fish of oxygen. An automatic CO2 system has a probe inserted into the tank which can detect when pH levels have dropped and will control the flow of CO2 accordingly.

While aquarium co2 systems such as Drs. Foster & Smith Deluxe Fully-Automatic CO2 System can be pricey, they can be a lifesaver for larger aquarium owners.

Final Thoughts

As an aquarium hobbyist, you have to learn how to create a harmonious balance among the KH, CO2, and pH because this will lead to the long-term sustainability of your fish. For most aquarium owners KH will never become an issue but learning how to raise KH in your freshwater aquarium can definitely be helpful in areas with hard water.

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