Should You Use Beneficial Bacteria, UV Technology, or Algaecide to Treat Green Water?

Green water has a tendency to make water gardening a nightmare if it happens to you, but during warmer months this can become a common problem for hobbyists.  There are so many things your immediately told to try to resolve this change quickly. You have heard about beneficial bacteria, UV technology, and algaecide, but which should you use.  Here is our guide to see which solution to use with your pond.

Beneficial Bacteria

Beneficial Bacteria is a water treatment used to reduce the nutrient load in a pond.  Green water is a result of algae growing in a pond. Algae is a plant that needs nutrients to grow.  If beneficial bacteria is added to a pond it competes with algae for the nutrients it needs to grow. This option for combating algae is best used as a preventative measure to stopping green water in the first place; however, it can be used over a long period of time to naturally reduce green water gradually.

UV Technology

UV Technology is an option to remove algae from the pond at the microscopic level.  It uses a UV bulb to expose algae at a microscopic level in the water to the light that breaks the algae apart.  If you are seeing green water in your pond, the algae is already larger than the microscopic level. UV technology can therefore be used as a preventative measure.  I can also be used when you are seeing green water, but since it works at a more microscopic level it make take a bit longer to treat the whole pond. If the algae in your pond has started to form a more solid shape on the surface of the pond or on the rocks in you pond, UV technology will not work to remove this as it only treats the water that passes by the UV bulb.


Algaecide is an option to remove green water from a pond.  It is a water treatment that can be used after you notice a green hue in the pond.  This is not meant to be used as a preventative treatment. The dosing with algaecide is important to take note as adding more than the recommended dose is not more helpful or fast acting to the treatment of algae, but can cause damage to fish and plants.  It is also important when using an algaecide to make sure the pond is well aerated to ensure healthy oxygen levels in that water that fish need to breathe. Since algae is the fastest algae treatments, it removes the algae at a rate that noticeably can impact the oxygen levels in a pond if the algae, as a plant, was a common aeration source for the fish.  If you are looking for faster results, an algaecide is a great option but it does require that additional oxygen source.

Finding the best solution for green water can seem overwhelming.  Should you use beneficial bacteria, UV technology, or an algaecide?  Now that you know about the difference is in algae treatment options, you can easily find the best option for your pond.