Sponge Water Filters Clean and Circulate Water

A sponge water filter can effectively clear and circulate water for a cold plunge:

Aquarium or fish tank. Sponge filters are commonly used in small or low-flow environments, such as breeding tanks or tanks with delicate or slow-moving fish. They provide biological filtration by hosting beneficial bacteria that break down harmful substances in the water, contributing to water clarity and quality.

The design of a sponge filter involves a porous sponge that serves as both a mechanical and biological filter. Water is drawn through the sponge by an air pump or water pump, which creates a gentle flow. As the water passes through the sponge, debris and particles are trapped, acting as a mechanical filter. Meanwhile, the sponge's surface area provides ample space for beneficial bacteria to grow, aiding in the biological filtration process.

In addition to filtering the water, sponge filters also create water movement and circulation, which is beneficial for oxygenation. The upward flow of water from the sponge filter breaks the surface tension, allowing for gas exchange and oxygen to enter the water, promoting a healthy aquatic environment.  It also helps keep the water moving and move cold water up from the bottom to the surface and keep the temperature even throughout the cold plunge. 

Overall, sponge filters are a reliable and cost-effective option for small tanks or situations where gentle water flow is desired. They provide both filtration and circulation as long as you are changing the water frequently.  

I also use Epson salts in the water as well to help treat the water.  Epsom salts, or magnesium sulfate, can be used to adjust the pH of water, but their effect is limited.  

Can Epsom salts help keep the water sanitary?

Epsom salts, or magnesium sulfate, do not have significant sanitizing or disinfecting properties. While magnesium sulfate can have minor antimicrobial effects, they are not strong enough to effectively sanitize water and this is why we change the water often.

If you are looking to keep the water sanitary without changing it often there are other more appropriate methods to consider. Some common methods for water sanitation include:

• Chlorination: Chlorine is commonly used as a disinfectant to kill bacteria, viruses, and other microorganisms in water. It is widely employed in municipal water treatment and swimming pool maintenance.
• UV sterilization: Ultraviolet (UV) light can effectively kill or deactivate microorganisms by disrupting their DNA. UV sterilizers are often used in aquariums, drinking water systems, and other applications where chemical disinfectants are not desirable.
• Ozone treatment: Ozone is a powerful oxidizing agent that can effectively kill microorganisms in water. It is commonly used in larger-scale water treatment facilities, swimming pools, and spas.
• Filtration: Mechanical filtration methods, such as sand or cartridge filters, can remove particulate matter and some microorganisms from water. However, filtration alone may not be sufficient for complete sanitization.

It's important to choose the appropriate method of water sanitation based on the specific requirements of your application. Consider factors such as the volume of water, intended use, and the type of microorganisms you need to target. Consulting with a water treatment professional or a local health department can provide you with tailored guidance on maintaining water sanitation.

Sponge filters are very cheap and can be purchased on Amazon.  Here is one that I use and works just fine.  You can change the sponge often or just clean it with some hot water when you change out the water in the cold plunge.

Here is a cold plunge guide that will help you build one for yourself.