Orange Pond Services

Algae in Koi Ponds

How do I stop Algae in my Koi Pond? The Algae problem in Koi Ponds and Water Gardens has been a problem for every pond owner.

Today we’ll explain how to keep a pond clear. Hair algae or string algae and pea soup green water are issues for some pond owners. Take a few minutes and learn the main causes of algae in a pond. What can you do to prevent algae in a pond? What methods are there for a balanced ecosystem in my pond?

Things to consider:

What time of year do you get algae?

What type of algae do you have problems with?

Do you have koi and feed them often?

Do you use beneficial bacteria, diatoms, or barley extract in your pond?

Do you have a UV sterilizer, and is it helping you with the type of algae present?

 

Nowadays, there’s a ton of misinformation out there about why you have algae in your koi pond or water garden.

Today we will get to the bottom of this and figure out some of the causes and solutions to the algae growing in your pond.

Ask yourself these questions if you have algae in your pond.

Is the algae in my pond harmful or just unsightly and unwanted?

What are some of the causes of the algae growth in my pond?

Are there any products that fight against algae?

Is there anything I’m doing that is causing the algae to bloom?

Pond and Lake Algae Cleaning

Swimming pools must be cleaned often and hit with powerful chemicals to keep algae away. If you let it go for 7 to 10 days without a good cleaning and some good chemicals, you’ll see algae growing. Algae spores occur naturally, and once the chemicals dissipate, they’re the only organism left to take advantage of all the nutrients in the water, thus starting rapid algae growth.
As you can imagine, a koi pond or a water garden will have at least a million times more nutrients than your typical swimming pool. Two factors that lead to the type of algae you have are the source of the nutrients and the conditions around your pond.

Excess nutrients or biomass 

• Feeding too often
• Decaying plant material
• Runoff water from rain or sprinklers

Consider three factors that contribute to excess nutrients or biomass in your pond.

Number one, you might be overfeeding your fish or koi. When you do this, there will be excess waste in the water, meaning excess nutrients, and this can cause an algae bloom. Number two, when old plants die and they decay that also adds nutrients to the water that we might not need.

Number three, when you have access to runoff water from rain or from sprinklers, excess nutrients can come just from that water and cause algae blooms.

Environmental Factors

• Excess Sunlight
• Rapid Water Changes

Two possible environmental factors can cause significant algae blooms. One is having too much sunlight. Yes, it is possible to have too much sunlight. 

The second factor is a water change, whether by adding or taking away that can remove very beneficial or harmful bacteria and diatoms.

If your pond is not at least 40% covered by floating plants or lilies, you have a much larger chance of having an algae boom because algae love sunlight.

If you have at least 60% of your pond covered by floating plants or lilies, you can almost guarantee that you will not have any algae because the algae will not be getting nearly enough sunlight to bloom.

Now I was talking about water changes.

First and foremost, when you have a brand new Pond, it is expected to have an algae bloom within the first two weeks. The Pond needs to go through what we call cycling, which is getting used to itself. In this at least two-week period of cycling itself, we do not recommend adding in any fish as the pond is not ready to be a healthy environment for the fish.

Whenever you add a lot of new water, meaning you’ve taken some water from the pond and now you are adding some new water, even if it’s not chlorinated, it can take away a lot of the already established healthy bacteria and diatoms that have been keeping the pond clean. 

These changes might cause an algae bloom.

Types of Algae

• String Algae or Hair Algae
• Green Water
• Film of Algae on the bottom of pond

There are three types of algae that we commonly deal with in ponds.

Number one is string algae or hair algae. String Algae can be removed by hand. It grows on rocks, waterfalls, the pond’s side, and even on unhealthy plants. 

Number two is green water. These algae are single-celled and are not connected to one another physically. They’re individual floating organisms in the water that gives the water a green appearance.

Number three is film algae. Not longer than a quarter inch covering the walls and floor of the pond or stones in the water.

Now we’re going to talk about what products are useful and what products are not useful to stop algae from growing. 

Algaecides

These products often say they are fish and plant safe, but if used improperly, they will kill or damage both fish and plants.

Note that by zapping the algae, you are not removing the nutrients from the pond. Rather you are converting them temporarily from a green living organism back to a free-floated nutrient that will become algae again when the chemical dissipates.

A second side effect of algaecides is that the rapid release of decaying algae in the pond can become ammonia, which is toxic to fish. Any ammonia spike can cause the fish to die. We do not advise using chemicals for an algae issue.

Ultraviolet Sterilizers

This product is only good at temporarily killing the green free-floating algae which can pass through the unit. The algae is killed by UV radiation, but remember, the dead particulates are food for other types of algae, such as hair algae. Hair algae won’t move through the unit, so that is one negative.

Be sure you have an active biofilter with aged bacteria added to the pond and plenty of plant life. In these situations, UV sterilizers are suitable for solving green water problems.

UV bulbs should be changed out every 12 months. Be sure the pump used with the UV light is not pumping too fast through the unit. If the water passes through too fast, the algae cells will not die.