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All About Algae

All About Algae

Pond Maintenance & Care 🕔February 3, 2020

Keeping Algae at bay while maintaining a balanced ecosystem should be the ultimate goal for most pond owners. It is possible, but it takes time for this process to occur. First we need to understand a little bit about algae, then how to control it in order to decide upon which methods or approach you choose to take to care for your pond or water feature.

What are Algae? Algae are a varied group of simple, photosynthetic plant-like organisms that live throughout the world in diverse environments. Most live in either fresh or saltwater, ranging in size from single celled or microscopic (many may only be truly seen individually under the microscope) to several inches or even feet (kelp).  

What are Algae Blooms? “Algae Blooms” is a term used when we experience an explosion of excessive algae growth which causes an unwanted abundance or “bloom”.  These blooms happen when several factors are in place: excessive sunlight, abundance of nutrients, slow or stagnant flow and warm water conditions. We avoid blooms in our ponds as much as possible as they can cause problems with water clarity and may also negatively affect your fish if they are getting caught in it or suffer from depleted dissolved oxygen levels.  Algae blooms may also affect how your pond runs- the pump and filters could get clogged up decreasing water flow. Make sure you always keep debris from restricting the pump intake.  The good news is that algae blooms happen fast, they don’t last forever and there is a way to break the bloom cycle.   Learn more about the Nitrogen Cycle below.

Green Water is planktonic algae that has multiplied quickly causing “blooms”

Types of Algae– there are 3 main categories of Algae that live fresh water which are based upon how they grow in the water. You may experience them at some point throughout the season at various times of the year.

  1. Planktonic– Single Celled Algae, free floating or in groups. These cause “green water” sometimes it can look brown, red or even yellowish. Often happens during warm weather. One of the most common types of algae- which can happen very fast and be really frustrating. Best control methods are with treatments-algaecides & beneficial bacteria; UV Clarifier or Sterilizer; and increase overall filtration (filter and/or increase amount pond plants, especially) floaters like Water Hyacinths & Lettuces.
  2. Filamentous- String or Carpet Algae. May be free floating in masses or attached to rocks or liner in groups forming long filaments. Large, diverse group. Commonly found in streams and on rocks.  Can happen in warm or cold weather, after a rainy period and in ponds high in Calcium or Phosphorous.
  3. Macrophytic – plant-like and visible seen. The two most common are Chara and Nitella which look similar. These are more common in lakes or large farm ponds rather than back yard ponds.
Many types of algae can be found in large groups or colonies that free float in the water. Other types are filamentous, commonly referred to as “string or carpet algae”

Controlling Algae– You need to figure out which types of algae you have and how you choose to control it. Refer to Why we get Algae followed by Control Methods.

Benefits of Algae- A bit of algae is not the worst thing for your pond. Like a weed in your lawn, Algae is an indicator that can tell you a lot about your what is going on in your pond.

  • Bioindicators – are valuable for indicating environmental quality. Blue Green Algae (Cyanobacteria) is usually found in stagnant, nutrient rich, poor quality water. Green Algae (Filamentous or Planktonic) is the most common types and are usually indicators of better quality water.
  • Produce Oxygen – as a waste product of photosynthesis. They produce more oxygen worldwide than terrestrial plants. Cyanobacteria can fix nitrogen in the atmosphere
  • Clean Water– Algae can help purify water by absorbing nutrients and heavy metals.
  • Contribute to the Food Web- they are the basis for many aquatic food webs. Algae is food for many invertebrates, that are eaten by birds, wildlife and fish. They are also important in providing habitat for fish, invertebrates and many larvae.

Toxic Algae. There are also many types of toxic algae, especially at high levels- they are usually Blue-Green, Red or Brown algae species- that are harmful if ingested by humans, pets and wildlife. You may also avoid contact with infected water on broken skin or in eyes. Most of these types of toxic algae species are more commonly found in still or stagnant lakes and farm ponds, rather than the typical backyard pond. 

Why we get Algae– Algae happens in just about every pond at some point. The trick is to keep those levels to a minimum by creating a balanced ecosystem a process that takes time to develop. Algae forms as a result of Nature trying to achieve balance.    

  • Excessive Sunlight- penetrates the water surface increasing light and heating up the water temperature.
  • Excessive Nutrients– fish waste and uneaten fish food. Overcrowded pond.
  • Inadequate Filtration- most ponds are under filtrated! Often when ponds are initially installed, inadequate filtration is chosen which is very common usually due to the extra cost. Additional filtration (pressure filters, bog filters, bead filters) can be added to your pond as needed and as your budget allows. Adding plants and using beneficial bacterial treatments can also help your ponds filtering ability.
  • Still Ponds- Aeration is important to all life in the pond. We strive to produce adequate dissolved oxygen levels through moving water from pumps and aerators that bubble oxygen. This helps our plants and fish grow and thrive as well as beneficial bacteria that work on dissolving the excessive nutrients and toxic chemicals like ammonia.

Nitrogen Cycle– Now we need to discuss the Nitrogen Cycle– an important & natural process that eliminates and consumes nutrients in all ponds and waterways reducing algae problems. Once we understand this, it helps us understand why algae is formed and how to reduce blooms while balancing our ponds ecosystem.  The Nitrogen Cycle happens in soil as well as water, but our focus is on how this process is responsible for biological filtration through Ammonia conversion called Nitrification.

Beneficial Bacteria convert Ammonia in Nitrate plants use as Fertilizer!

This process starts with Ammonia – that comes from Fish Waste and Decaying Algae & Debris- high levels are toxic to fish. Two types of bacteria then convert Ammonia (high levels are toxic to fish) to Nitrites  by Nitrosomas which are aerobic bacteria (likes oxygen) then to Nitrates by Nitrobacter bacteria. Nitrates are then consumed by plants and algae. If you have few plants or inadequate filtration, Algae then tries to fill the role as “plant” in the cycle in order to help balance the system- nature’s aquatic equilibrium. 

Use individual teat kits, master test kits or strips to determine your Ammonia and other water quality levels.

How do you check your Ammonia levels? Use test kits on a regular bases, especially if you are new to pond care or if you have a serious issues. Even if your water is clear, it still may off in water chemistry levels. Read more about water chemistry in our water treatment blog.

 What helps to balance the Nitrogen Cycle?    

1. Beneficial Bacteria Products – adding regular treatments- weekly, or 1-2 times a month. Use more often if your pond is new, just cleaned or sludge is present; add daily or a week then add weekly once water quality has improved.

2. Pond Plants – help absorb nutrients broken down by benficial bacteria.

3. Great Filtration – keep excess waste and debris out of your pond. Don’t over feed your fish.

Read more below about balancing the nitrogen cycle while reducing algae levels.

Algae Control Methods- there is not one simple way to control algae. Continuous use of algaecides alone will kill algae, but then the dead algae will become fuel for the next algae bloom repeating the cycle. Using beneficial bacteria products a few days or a week after treating algae will help to break that cycle- eventually- after multiple treatments. You may even find that frequent use of beneficial bacteria treatments will reduce algaecide dependence. This may vary seasonally, what is best is to get to know your pond intimately. Keep in mind that every pond has its own unique environmental factors, so what works well for someone else may not work for you or even be necessary given your situation. Our goal is to strive for a balanced system, using multiple methods that balance each other. 

  • Add plants- help to out compete with algae, shade the water and decreases nutrient levels.
  • Add Treatments- beneficial bacterial & algaecides, as needed.
  • Increase Filtration – Add filters, plants.
  • Increase Aeration– remove stagnant areas and ponds. Keep running continously- 24/7
  • Decrease Nutrients in Pond– Fish food & fish wastes, runoff from soil, bark & fertilizers. Do not over feed your fish or leave uneaten fish food in your pond that provides food for algae.
  • Physical Removal- hand remove large clumps of algae whenever you can with a net or algae twister/brush (toilet brushes work well)
  • Regular Cleaning– Weekly Maintenance is important during Spring thru Fall with less needed during winter months. Complete Clean Outs are typically done yearly or every other year depending upon how much debris is in your pond, how many & how big your fish are and your filtration.
Use Alagecides like Clean Max, then follow up with Beneficial Bacteria products like Aqua One.

Using Algaecides– Continuous use algaecides alone will kill algae, but then the dead algae will become fuel for the next algae bloom repeating the cycle. Using beneficial bacteria products a few days or a week after treating algae will help to break that cycle. You may even find that the more you use beneficial bacteria; the less algaecides will be needed.

Also, very importantly- always use caution when using algaecide treatments, especially if you have fish, follow the directions and do not over- dose!  Do not allow your skin, get into your eyes or mouth and always keep products way from children & pets.

  • Avoid using during hot weather, over 85-90 degrees F. Best to wait until a cooler day or treat at night.
  • Maintain Aeration– algaecides consume oxygen as they work. If oxygen levels become depleted, fish may suffer and eventually suffocate. This stressed behavior happens when fish come to the waters surface and gasp for air- if they do- you don’t have a lot of time. Add additional aeration with an air pumpand stones; another pump to move water or drain 10-20% of your water and add fresh water from the hose.
  • Algaecides preform better when you have algae, rather than solely as a preventative. Excess algaecides have been suspect to unanticipated fish deaths, even if the bottle says it is fish safe. Make sure you are home for several hours after initial treatment with an algaecide in case there is a problem.

Other Treatments for Algae-

  • Barley straw is an alternative method for “controlling” excessive algae growth. It is most effective when applied early in the year prior to the appearance of algae. Applied to cold water (less than 50°F), it may take 6-8 weeks to activate; warmer water (above 70°F) only 1-2 weeks. Barley straw remains effective for approximately 3-4 months after application.Barley straw does not kill existing algae, but it inhibits the new growth of algae. Barley straw, when exposed to sunlight and in the presence of oxygen, produces a chemical that inhibits algae growth.
  • Barley straw does not reduce the growth of other aquatic plants. In some cases aquatic plant growth has increased after barley applications because algae are no longer present to compete with the aquatic plants. How often to Apply Barley: Spring, Summer and Fall (straw); Barley Extract use as Directed. Place bales at several locations around the pond and especially near streams & waterfalls. They should be near surface, not floating (they may sprout) weighed down with fishing line or rocks.
  • “Oxy-Pond” Cleaners. These are granular products that are sprinkled directly on algae that kills and consumes through oxydization. Do not get these products on plants you want to keep and limit how much you use if you have fish. These products work really well in bubblers, fountains and “pond-less” waterfall features. Follow up with a sludge reducer or beneficial bacteria product a few days or a week.
  • UV Clarifiers / Sterilizers. These devices usually sit outside the pond and need to have water running through it at a slow rate depending upon what size you are using. Can be used “inline” or added later with an additional pump to push water through it. The UV bulbs have a certain amount of “hours” that need to be replaced every year or so depending upon how long you run them. Read the manufacturers installation and care instructions. UV Clarifiers take care of “green water” only and will not help with string algae. We have a great selection and several sizes of UV units, bulbs and quartz sleeves. Stop into our store so we can help. We also have pressurized filter units that have UV’s inside them making for the perfect combination. Check out our Pondmax Filters we have several sizes in stock.
  • ION-Gen. Ultra-Sonic Algae Controls. ION-Gen is another unit that helps control String algae in ponds. There is a metal probe inside of a T fitting that sits inside your pond – usually in the skimmer- and a controller to set your level from high to low. This is easy and works really well once you get the hang of it. You will need to replace the metal probe every year or so. For more about ION-Gen read here Stop in our store and get yours today! We also have replacement probes.

If you are having problems with water quality, stop into our Pond Supply Store and we can help you find solutions. If you are not local to the Olympia, WA area we do offer Email Consultations for a small fee. Inquire at Ke*****@Na***********.net