How can I reduce (and limit) algae growth in my pond at the beginning of the season?!

How can you remove filamentous algae from a pond at the start of the season? If you have a pond, you may be faced with the problem of these rather invasive algae. These algae always tend to appear during the month of February, when temperatures rise and there is more sunlight. 

Are these algae in your pond bothering you and are you looking for a solution to limit them? How can I reduce (and limit) the growth of algae in my pond at the start of the season?! 

In this mini-guide, there are 4 essential steps before spring: 

1. Restart your filtration system.
2. Vacuum the sludge from the bottom of the pond.
3. Analyze the water quality. 
4. Mineralize your pond and correct the water parameters. 
5. Use a treatment suitable for the water temperatures. 

How to remove filamentous algae? 

Rest assured, there are several solutions to limit, or even eliminate the presence of filamentous algae in your pond. It is important to act as quickly as possible, using the right method. If you delay taking action, it will be more difficult to get rid of them. On a sunny day, algae can double in volume per day. 

• Temperature > 12°C => standard algae treatment
• Temperature < 12°C => greenstab or elbow grease :-) 

Algae tend to grow especially in early season, when aquatic plants are in their dormant period. During the season, aquatic plants will compete with algae, and reduce the amount of nutrients available to algae.

The first thing to do in spring to limit algae is to restart your filtration system and vacuum the sludge if necessary. 

Next, the second thing to do is to perform a water analysis with the right equipment. You will need to check several parameters:

• pH
• GH
• KH
• NO2

It is important to check GH+ & KH+ to balance the pH. Good water hardness (GH & KH) is also a protective barrier for the fish in your pond. You need to "mineralize" your pond after winter, because rainwater causes water hardness to drop sharply. A natural pond is generally constantly fed by springs, which helps maintain high water hardness. 

⭐ Important: before performing an algae treatment (which you can find here), it is essential to check the hardness (GH and KH) of the water in your pond. You should not perform this treatment if the hardness is not corrected.

⭐ You may also be interested in: our guide to analyze pond water

If necessary, also check the phosphate and nitrate levels. You can purchase a test kit (see photo below), which will allow you to analyze these different parameters in a few minutes.

Why do I have algae in my pond? 

Algae can appear for several reasons in a body of water. In most of the situations we encounter when visiting our customers' ponds:

• Overpopulation of fish
• Filtration too limited for the volume (or turned off) 
• Too many nutrients in the water
• Not enough aquatic plants (or spring) 
• Very clear water (lots of UV in the pond)
• Poor water quality 

You need to distinguish several things: internal and external factors

Why fight the proliferation of algae?

First, know that filamentous algae maintain the balance of your pond. But their presence has significant consequences, both negative and positive. If these algae are present, it is often for several reasons:

• Overpopulation of fish
• Not enough aquatic plants (or spring)
• Insufficiently maintained filtration or a filter that is too limited

When water temperatures are too cold, it is sometimes unavoidable to treat the algae. If the water is below 12°C, you should avoid algae treatments such as Algisin. If the water is cold, opt for a treatment like Greenstab (found right here). 

The growth of filamentous algae occurs naturally, even in a difficult environment. Their appearance is explained by the presence of three factors:

• Water temperature
• Sunlight
• Nutrients in the pond.

Even if you have poor water quality, the growth of filamentous algae is always possible. This is also sometimes the case in good quality water.

What solutions are there to limit filamentous algae?

To fight the proliferation of filamentous algae, you can opt for different types of solution (found right here):

• an algae solution (Biobooster, Algisin, Greenstab)
• a natural solution (like Aquipond Eco AlgControl)

⭐ You may also be interested in: the presentation of Biobooster+, a miracle product for aquatic ponds

Attention, for most algae treatments, you will need to wait until the water is at least 12°C. In case of too low temperatures, opt for suitable treatments found here. 

Natural solutions to get rid of filamentous algae

If you do not want to use chemical products, it is perfectly possible to choose natural solutions to limit filamentous algae. For example, you can use Aquipond Eco Alg Control (made from barley straw). 

Pond cleaning

First, a partial (or complete if necessary) cleaning of the pond is necessary, consisting of removing the plants using a specific vacuum. A particularly effective solution, because not only will you get rid of filamentous algae, but also all the nutrients used for their nutrition.

Use beneficial bacteria

Beyond using the vacuum, it is recommended to use beneficial bacteria. Use living organisms that will aim to limit the filamentous algae in the pond. Indeed, you should know that beneficial bacteria are capable of feeding on excess nutrients present in the water.

Thanks to their action, the algae will gradually die. Beneficial bacteria are not intended to contribute to the death of these algae, but rather to regulate them. For the effectiveness to be there, it is necessary to follow the instructions. For example, by avoiding combining them with herbicides, otherwise the beneficial bacteria will die very quickly.

⭐ You may also be interested in: the list of oxygenating plants for a balanced pond

Is it possible to introduce animals that feed on filamentous algae?

Certain fish like herbivorous carp will allow you to regulate the algae in your pond. However, carp will be of no use to you if you specifically want to fight filamentous algae.

If you have unwanted plants, you can also use barley straw. It is a particularly interesting alternative to herbicides. Indeed, thanks to its presence, the pH level will then drop as well as the carbonate hardness of the pond. When the pH is below 8, algae like to develop less.

In these conditions, you have water with a better balance and you control the growth and proliferation of filamentous algae much better. As soon as the barley straw comes into contact with the water, it produces peroxide. A substance recognized for the elimination of unwanted plants.

Find below a few related articles that may interest you:

• Which plants filter pond water?
• Why is the water in your pond green?
• How to choose a pond vacuum?
• How long before adding fish to a new pond?