How to Clear Green Water in your Pond Quickly

When we are talking green water in the pond we are referring to suspended algae. Suspended algae are essentially small particles of algae that stay suspended in the water causing your pond to look like “pea soup” and not allowing you to see clearly to the bottom of your pond or see your fish. Let’s work on transforming your pond from!

From this To this

Many people are initially looking for a ‘quick fix’ to their green water problems and this is where we will address a product called Crystal Clear Pro Fix (Formerly known as D-Solv 9). This liquid product can be added once a week and can clear up your green water in as little as 24 hours.

Pro Fix (D- Solv 9) cleans and clears pond water in as little as 24 Hours.

  • May be used in ponds containing Fish and plants;
  • Application: Shake well before using. Should only be applied a maximum of once per week;
  • Should only be applied a maximum of once per week;
  • Application Rates:
    • 1 fl oz/30 ml - Treats up to 600 Gallons;
    • 2 fl oz/30 ml - Treats up to 1200 Gallons;
    • 4 fl oz/30 ml - Treats up to 2400 Gallons;
    • 8 fl oz/30 ml - Treats up to 4800 Gallons;
  • Ensure there is vigorous Aeration present when using this treatment;

What Causes Green Water?

Once you realize that green algae is a plant, it becomes easier to see what feeds that plant to grow and multiply in your pond. Green water requires sunlight and nutrients to thrive – thus it makes sense that a pond in full sun with no coverage will likely have more algae than a pond in the shade or with plant coverage.

The tricky part is realizing what nutrients may be entering your pond to feed the algae. Below are a few of the most common reasons for green water in your pond along with proactive tips to reduce the problem.

Potential Cause of Green Water How to Prevent the Issue

Too Much Sunlight Exposure/Pond is in Full Sun

Aquascape Pond Dye

For most, it is not a viable option to move ones pond to a different location – so to create more shade in the pond there are 2 options that work great:

Pond Dye – fish and plant safe, pond tint will add a hue of blue or black to your water to help filter out sunlight and many love the hint of colour as well – not to worry you will be able to see your fish easily through the tint as it is translucent!

Low Quality Fish Food

Crystal Clear Platinum Koi Food

  • Fish food quality is a hidden cause of green water that many people do not take into account. Particularly for the people with many fish that feed multiple times a day – the quality of your food makes a huge difference in water quality;
  • A pond fish will retain plenty of a quality food and its nutrients, but if the food is low quality – much of it will pass from the fish as waste and feed the algae in the pond. In this same category – uneaten food is a big no-no. Try feeding your fish whatever they can consume in maximum 5 minutes – any uneaten food should be netted from the pond;
  • Generally when it comes to koi and pond fish food – the better the quality – the more money the food is – however you will find the food to be more nutrient rich, which would allow you to feed less food while still having better growth.

Bacteria and oxygen levels are low

Microbe-Lift Bacteria

Pond Aeration Kit

Beneficial bacteria and oxygen are two vital components of a healthy pond and luckily both work in conjunction with one another. Beneficial Bacteria require oxygen to thrive and multiply. Both occur natural in ponds and lakes – the difference with ponds is that we overload much beyond that of a lake and expect mother nature to keep up – unfortunately, this rarely happens!

Lucky for us we can add aeration and beneficial bacteria to help Mother Nature along. Without enough bacteria and oxygen not only can the water become toxic to fish, but algae in the form of green water can fluctuate to unsightly levels as well. This is what we mean by looking for a balanced, mature pond with sufficient bacteria and oxygen to allow the pond to flourish.

Too Many Fish in the Pond

Aquascape BioBall

Too many fish is a common problem – sometimes fish multiple and grow faster than we anticipate. When this happens, the pond can no longer support the excessive waste coming from the overpopulation – it would be similar to an overcrowded city with excessive waste. In the case of a pond, excessive waste feeds the green water and can lead to harmful water quality that can be detrimental to the fish. How to combat overpopulation? Some will increase the size of their pond and others will part with some of their fish. Another option is to increase bio media and thus bacteria levels.

Waste from Falling Leaves and Cut Grass

Skimmer Net

Pond Skimmer

It may be great to have a large tree overhanging your pond for added shade, but there is often one downfall – leaves falling into your pond.

The same problem occurs if you are not careful and grass cuttings also make their way into your pond. All this added debris eventually begins to breakdown in the bottom of your pond and provide nutrients for that green water to thrive.

How to prevent? Many pond owners will install a skimmer (similar to that of a pools) to prevent debris from staying in their ponds. This option is a lot more maintenance free than your other options which is netting it out by hand. Some people will also net the entire pond – most often in the fall when the majority of the leaves will drop within a week.

Fertilizers Leaching into your Pond

This is a category that many pond owners are not aware of due to its lack of visibility. This can happen 2 ways:

  1. When throwing fertilizer for your lawn or flower beds, some of the fertilizer enters the pond.
  2. When there is a heavy rainfall, the overflow of water drains into the pond and with it the fertilizer used in the lawn.

This is why we often recommend that ponds are built in a raised area in the yard as opposed to a low lying area. As well, being vigilant to keep all fertilizers away from the pond.

New pond water/ excessively changing water

A lot of people believe that if their ponds are full of green water the best plan of action is to empty the pond, power wash it and fill it with new tap water. This option is great for the first couple days, but check back in a week and you will notice that green water coming back with a vengeance. The problem with this scenario is that we want to strive for a mature pond that has had the time to build up beneficial bacteria and have nutrient levels stabilize. When you empty the pond-power wash and refill, all of that new water is full of minerals and nutrients as well as your beneficial bacteria levels are practically starting from zero. This is why we promote small water changes (10-15%) weekly and work towards maturing our ponds with bacteria and oxygen (the fish much prefer this route as well!)

Products to Help Eliminate Green Water

Our first course of action with any pond issue is to be proactive – looking at the cause and trying to prevent the issue from happening. But when green water happens most of us don’t want to wait weeks to see results. Below you will see products that aid in eliminating green water (suspended algae) as quickly and effectively as possible.

Product Quick Overview What it Does/When to Use

CrystalClear D-Solv Oxy Pond Cleaner

Pro Fix is a water treatment that eliminates green water in as little as 24 hours. This product should be used maximum once a week and is safe for ponds with fish and plants.

Pro Fix is best used as a quick fix as opposed to a long term solution. Many people will use this product while they are waiting for their bacteria to mature and multiply in the beginning of the season or when we have heat spikes and the water takes a turn for the worst.

*use with aeration present.

UV Ultraviolet Clarifier

UV Clarifiers work on all water than can pass through the system, which means they work excellent on green water. Most will see improvement within a few days and full clarity within a week so long as the unit is sized correctly to the pond.

The pros of a UV Clarifier are that they are super effective with very little maintenance required and fast acting. The con is that the up-front cost is more than a water treatment, though many would agree that over the course of a year that it becomes cost effective compared to the on-going use of water treatments.

Pressure Filter with UV

Pressure Filters With UV Clarifiers incorporated are becoming the industry standard for ornamental ponds.

These units have all of the same benefits as a UV Clarifier with the added benefit of having sponge media to filter out fine debris, bio media to increase your beneficial bacteria load as well as an easy to use back wash system that squeezes out the sponges using a handle without the owner having to open up the filter and get their hands dirty.

Microbe-Lift PL

Microbe-Lift is a specially formulated Beneficial Bacteria that has stood the test of time and has become the industry standard for beneficial bacteria. It is a fast acting bacteria that does wonders for all aspects of the pond. Many pond owners will use this bacteria to start their pond, due to it fast acting properties and effectiveness.

This a trusted brand and product that has been a best seller for seeding filters and pond maintenance. Not only beneficial in clearing pond water, but also for maintain a healthy pond with proper nitrate cycle levels and therefore, healthy fish.

Beneficial Bacteria For Ponds Dry

Beneficial bacteria is a product every pond owner should use regardless of what filters, pumps and chemicals are being utilized in the pond. Beneficial Bacteria does not interact poorly with any other product. This is a product that we add to our ponds once a week as a maintenance dose and is very cost effective. The dry bacteria is more cost effective than the liquid, however the liquid bacteria is generally faster acting. This is why we often use the liquid in the early spring and late fall when we require more of a bacteria boost and use the dry bacteria through the remaining months of the summer/warm months.

*if you are going to add one product to your pond weekly – choose beneficial bacteria.

Beneficial Bacteria For Ponds Dry

Cold Water Beneficial Bacteria (Liquid)

Beneficial bacteria is a product every pond owner should use regardless of what filters, pumps and chemicals are being utilized in the pond. Beneficial Bacteria does not interact poorly with any other product. This is a product that we add to our ponds once a week as a maintenance dose and is very cost effective. The dry bacteria is more cost effective than the liquid, however the liquid bacteria is generally faster acting. This is why we often use the liquid in the early spring and late fall when we require more of a bacteria boost and use the dry bacteria through the remaining months of the summer/warm months.

*if you are going to add one product to your pond weekly – choose beneficial bacteria.

Rapid Clear

Rapid clear is generally not a product that you would use weekly as maintenance, but instead a product to fix an issue a few times a year at most. Rapid clear is a flocculent that takes fine debris in the water that is not settling and clumps it together to clarify the water. When trying decide whether your water requires rapid clear – decide if the water is just green or both green and murky. If murkiness is involved – you may require the use of rapid clear flocculent. Most often ponds may require this water treatment after large rainfalls, or if runoff has entered the pond. Also make sure your fine filter pads are not backed up

Filter Floss Bio-Media

Bio Media ties in with beneficial bacteria. Beneficial bacteria requires surface area to attach to – and because the more beneficial bacteria in your pond the better – we try to increase surface area available in the pond. The best way to increase surface area is using bio media, which can come in different forms - Filter floss media, bio balls, bio rings etc. All of this media takes up very little room in filters to provide maximum surface area for beneficial bacteria. A small investment for huge payback – every pond can benefit from have bio media and beneficial bacteria.