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Do UV Lights Work to Destroy Algae?

    There are two main types of algae.  The stringy fuzzy scummy type that sticks to your rocks or on the surface of the pond.   A UV Light will not help at all with this commonly seen type of multi-cellular algae.

    The second type of algae is what most people call green water.  This type is a single cell algae that is suspended in the water and makes it look green.  Unlike the first type that you can touch and feel this single cell green water algae is not able to be removed by hand.

    A well-designed ecosystem pond will have a circulation system that uses a skimmer to remove debris and a biofilter to process excess nutrients.   This process starves the algae and prevents it from causing your water to turn green.

    Learn More about Pond Ecosystems


    If you have a green water pond it is because of the excess nutrients.  

    You have two choices –

    PREVENT it (green water) by removing the excess nutrients and starve the algae. 


    Let the algae flourish and then try to KILL it with a UV or algaecide.

    What is Pond Algae?

    Algae describes a diverse group of organisms that thrive in nutrient-rich environments like a poorly built backyard pond.  

    A well-built pond, like the ones we design at Splash, will prevent algae from making your pond look like pea soup  by creating a natural environment where beneficial bacteria can thrive and consume all of the nutrients algae would need to grow.  Because of the way we design our ponds here at Splash, we have never in our 35+ year history had to use a UV light in a Splash Ecosystem Pond to get rid of green water algae.

    Related: The Ultimate Guide to Clear Pond Water

    Hold on a second …  I have a skimmer and a biofalls and I still have problems with green water, what am I doing wrong?

    If your pond has a skimmer and a biofalls and you are still experiencing green water then something is amiss.  Here are a few common maintenance issues that could be contributing to your green water:

    1. If you are cleaning the filter pads in the biofilter more than once a year this could be the cause of the green water in your pond.

    2. Your skimmer or pump is not big enough.  Put a leaf in your pond as far away from the skimmer as possible.  You should be able to watch it get pulled into the skimmer  within a few minutes.

    3. Excess fish or excess feeding.  If fish food is going into your skimmer you are putting too much food in the pond that is being wasted and adding unnecessary nutrients to the pond.

    4.  Your biofilter should be large enough to handle all of the excess waste from your fish and all of the debris that is breaking down in your pond.  If your filter is too small you could experience green water.

    5. Your pond is new.  New ponds can take a few weeks to a few months to get a balanced ecosystem established.

    But what about UVs?  Is there ever a time to use one?

    Not every pond is designed to the standards of a Splash Ecosystem Pond.  We do sell UV Filters at Splash and they do work.  If your pond has green water stop by Splash today and let us show you our line of UV lights. These lights are designed to kill the types of single-cell algae that flows past the bulb.    UV bulbs do not have any impact on stringy fizzy algae because that type of algae typically sticks to your rocks and does not flow past the bulb.