There are two main types of algae commonly found in ponds:
- Filamentous Algae – This is the stringy, fuzzy, or scummy type that attaches to rocks, waterfalls, and other surfaces, or floats on the pond’s surface. It’s multi-cellular and can be physically removed by hand or net. A UV light will not help with this type of algae because it does not pass through the filter system.
- Planktonic (Green Water) Algae – This is a single-celled algae that floats in the water. It makes the water look green and it can’t be removed with your hands. A properly sized UV clarifier can sometimes kill this form of algae by killing the cells as they flow past the UV light.
Should I install a UV on my Splash Ecosystem Pond?
A well-designed Splash ecosystem pond naturally keeps algae under control by reducing the nutrients that cause green water.
Your skimmer should be removing 70-90% of the debris that gets into your pond before it gets into the ecosystem. Your biofilter will easily handle the remaining nutrients and breaks down the ammonia and nitrites into nitrates.
This process essentially starves the green water algae. The fancy word for this is Oligotrophic. This means a pond with very little nutrients to support algae.
Although, we sell UV calrifiers, we have never needed to install a one to control planktonic algae in a properly designed Splash ecosystem pond.
When your pond is well built and well-oxygenated your water will stay clean, clear, and healthy – naturally.
Bottom line: A UV is not needed because planktonic green water algae never grow in a properly built Splash Ecosystem Pond.
Excess nutrients are the cause of green water — planktonic, single-celled algae feeding on nitrites, growing, and multiplying in your pond.
You Have Two Choices — Proactive or Reactive?
✅ Proactive = Prevention
Stop green water before it starts.
Remove excess nutrients (the food algae need to grow).
Maintain a balanced ecosystem that naturally starves the algae.
→ Clear, healthy water — the natural way.
⚠️ Reactive = After the Problem
Let the algae flourish… then fight it.
Use a UV clarifier or algaecide to kill existing algae.
Temporary fix — the nutrients are still there and now you have more nutrients from the dead dying planktonic algae – making the problem worse!
→ More maintenance, more cost, and less balance.
Splash Recommendation:
Be proactive, not reactive.
A well-designed Splash Ecosystem Pond keeps water clean, clear, and healthy — naturally.
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.
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.