Image courtesy of Terling

Building a water garden pond is an immensely rewarding experience, one that gives its builder an enduring sense of accomplishment in addition to creating a beautiful space in which to meditate and entertain. And it’s not as complicated as you might think. Although pond building and water garden landscaping can take many forms and attain many levels of complexity and difficulty, designing, installing and landscaping your own pond is an entirely achievable and enjoyable project for the determined do-it-yourselfer. The basic overview below explains the bare basics of how to build a backyard pond of your very own. It is intended as an introduction to pond building, and should serve to give you a preliminary point from which to seek out additional research, gather materials and begin working toward the planning and “planting” of your first water garden.

Step 1: Every successful project starts off with a good plan. Once you’ve decided to undertake your own pond construction, you first need to come up with a solid, well-researched design and plan it out in full detail (this includes making scale sketches, plotting out the size and shape of your pond on site, evaluating the optimal location, playing with different styles and designs, etc.). Having a good plan in place before you even purchase materials is the best way to save time, effort and money by preventing common mistakes and miscalculations.

Step 2: Start to gather the materials you will need to operate a clean, clear water garden pond. As a first-timer, you can save yourself a lot of headaches, effort and cost by choosing to start your project with one of the many quality garden pond kits on the market. Pond kits come in nearly any size and style, and, what’s more, include all the basic parts and instructions necessary to install your pond – all pre-selected for compatibility and typically offered at a much lower cost than purchasing each component separately. Choosing a complete pond kit over a custom, search-and-purchase approach will help ensure your first installation goes as smoothly as possible.

Step 3: Prepare to start digging. When you’re officially ready to begin building, mark out your pond’s outline with spray paint, flour or another visual medium and start digging. Begin by making the surface of the ground – around where you’ve drawn your outline – as level as possible before moving on to any vertical digging. This will ensure your final water height will be the same on all sides. Move on to digging out any planting shelf areas and, finally, complete your pit by digging down to and leveling the bed area. Depending on the size, depth and shape of your pond, the excavation can take several hours to several afternoons. Pause often and check yourself to ensure you’re getting the right shape and depth, and reserve the excavated dirt to be used later for any stream incline or brim.

Step 4: Remove any sharp rocks or roots and install your underlayment first and then your liner. You may choose to put down a layer of sand first for additional protection. If using a flexible liner, make sure to overlap the underlayment in places where you need to “patchwork” it into shape. If you need to overlap your liner, use a seam kit to create a watertight seal on all seams. Depending on the type of liner, waterfall and skimmer you use, you may need to install these components first, and cut the liner to fit around the skimmer and waterfall tank. Follow the instructions for your particular pond kit, or consult the advice of a professional. Leave some extra underlayment and liner exposed around the edge of your pond during construction, so once you get your waterfall running, you can determine if you need to further build up your stream area to accommodate the final waterfall depth.

Step 5: Install your pump, skimmer and waterfall filter if you haven’t already, again, following your pond kit or advisor’s instructions. Using a ground fault circuit interrupter (GFCI) to safeguard your outdoor outlets from water damage is highly recommended, as is getting a professional’s help if you are not familiar with electrical work.

Step 6: Once all the working elements are in place, fill your pond with water. Run your pumps and filters and check to see if everything is operating smoothly before you start landscaping. Having to tear out all your hard work in order to fix a component problem is no fun.

Step 7: Water garden landscaping is arguably the most enjoyable aspect of pond construction. A variety of natural stones, aquatic plants (water lilies, oxygenators, partially-submerged, submerged, floating and marginal plants) and even several species of fish can be used to create the look you’re going for. When building a water garden pond on your own, everything from a natural-looking do-it-yourself waterfall to a more contemporary stacked-stone meditation pool can be achieved with a little concentrated effort and creativity.

About the author: Garth Epp is the editor of www.BuildingMyPond.com and the host of the Smarter Water Garden Advisor Series Pod Cast. It is his objective to provide unbiased information on building water garden ponds and waterfall features. His aim is to provide guidance and education on all aspects of building and maintaining your own pond.

On Garden Pond

Building a water garden pond in your own backyard is something many dream about, but few accomplish. Many factors work together and help to put people off starting the process, and yet others are daunted when they are faced with a choice of pond kits and don’t know how to start choosing which one will be right for them.

Price is often a sticking point, decisions about where the pond and waterfall would be located in the back yard (or even front). Labour costs, cost of delivery of the items, the logistics involved in a DIY job which require heavy lifting equipment. Then there is the cost of water, considerations regarding planting, how to do it and how to maintain the pond. And that is before you even start buying the Koi to swim in it.

Here’s some points to consider when planning to build a water pond:

1. Decide what your budget is for the project – Best advice here is a DIY project costs less than a professionally laid out job, simply because you save on the labor costs – do not try and save on the cost of the materials. For long term satisfaction and cheapest installation – buy the very best materials you can afford. Think long term and in terms of cost-spreading over a long period of time rather than the initial short term expense. For example; buying a rubber liner costs more up front, but lasts more than twice as long as your other options.

2. Decide where you would want it to be located. Look at the proposed site from both inside and outside of the house – view the area through your ‘common space’ windows and make sure that you – and not your neighbors, are getting the most benefit from your investment.

3. Choose what type of do it yourself waterfall you want to have in your water feature. The decision about the waterfall governs the size of the pump that you will need to choose in order to give you optimum water flow and filtration. Likewise – the budget you will set aside will govern, ultimately, the size feature and thus the size waterfall you can install.

4. Choose a water garden pond kit instead of trying to purchase all the liners, pumps and filtration units as separate items over a period of time. You actually spend less by saving up and then buying a kit outright that suits your budget than doing it piecemeal. By the time you can afford the next bit of kit, you may well have to go back to square 1.5 to install it. This wastes time, which ultimately costs money.

5. Do not skimp on ‘small’ items such as liner sealing kits. Water creeps out of a liner if the edges of two sections are not made watertight. Water is expensive and the price of the sealant kit is less than constant refilling and losing your fountain because the water level has dropped below critical level.

6. Planting your water pond need not be as expensive as you think. Much of the expense of setting up the plants in and around the water is the purchase of exotic plants and imports. Buy local plants which grow well and suit your environment. While not quite as spectacular (because you see them around you every day), they are more likely to survive the local conditions and weather. Choose plants which are suited to a wet environment.

7. Do not be afraid to call in a professional consultant. Suggestions and constructive comment before you start a project can mean the difference between success and failure when building a garden pond. Sometimes pod equipment suppliers will have a consultation available both in-store and online who can advise you. If you choose buy the your equipment from them, you can even get that advice for free.

In short, it pays to do your homework and plan out your project before you start. You will be rewarded in the end with an amazing water feature if you carefully plan ahead before you start digging up your yard. The end result will be a great place to go, sit back, relax and forget the worries of the business of life. The sound of the water lapping against the rocks will drown out the sounds of the human world. Even though this oasis is manmade, when properly planned and built, your created water garden feature will become part of nature’s beauty for you to admire for years to come.

Garden ponds create a tranquil space within any backyard garden. In order to keep your garden from becoming a mosquito factory, you need to build movement into the water. What better way than building a garden waterfall? It is easier than it sounds, and your pond will be healthier for it.

Waterfalls keep pond water oxygenated, which helps plants growing in the water. Waterfalls also keep water moving, which is essential to avoid producing mosquitoes. (Did you know that one lady mosquito can produce 2,000 baby mosquitoes during one season?) Water movement also helps avoid growth of certain types of algae.

Garden Waterfall Basics

Garden waterfalls require pumps and filters, along with other equipment. As a novice waterfall builder, it is a good idea to buy a waterfall kit that provides the basics. The size of the pump and the filter (and therefore your choice of waterfall kit) will depend on how large your pond is, and how much water you want to move. A chart called the “waterfall weir chart” will help you determine the pump size. When calculating the size of the pump you need, you must consider the amount of water, the distance and the width of the waterfall.

A good rule of thumb for designing a waterfall is to use the third/third/third rule. Use one third water, one third hardscape (rocks) and one third plants to complete your design. You can artfully place rocks and stones in the waterfall to influence the way the water spills and splashes down to the pond.

Backyard waterfalls are aesthetically pleasing and calming. Not only do they add an extra dimension to your garden, they also function as a natural system to keep your garden pond healthy without the addition of chemical treatments.

When the beneficial pond bacteria becomes unable to degrade the waste in a timely manner, oxygen levels can drop and anaerobic bacteria starts to become prevalent producing hydrogen sulfide (odors) and poor water quality. By adding back into the pond commercially available beneficial pond bacteria, you are creating a scenario where the beneficial bacteria is once again outnumbering the bad bacteria and creating an ecological balance with in the pond again.

Because you never know exactly when your pond could get out of balance, it is highly advisable that pond owners add beneficial pond bacteria on a regular basis as often as weekly, but no more than monthly, depending on the pond. Also, because the good bacteria are highly influenced by oxygen, their benefits are greatly increased with the presence of an aerator or fountain. However, many of the pond bacteria formulations on the market today are created with beneficial bacteria that can exist with oxygen or even in very low oxygen levels.

A little can go a long way. Never has that been truer than in the case of pond maintenance. Sure, every pond is different and there is some very technical and biological information that is very important for the maintenance of a pond. However, being armed with some basic knowledge in a few key areas can be a great start in becoming a confident pond owner, no matter if you own a larger pond like a farm pond or smaller more intensive koi pond or water garden.

WATER CHEMISTRY

You don’t need to be a biologist or chemist to keep your pond water clean and healthy. While undoubtedly having that sort of background helps to understand all of the processes that take place in a pond, a simple crash course in pond water chemistry can go a long way to helping the average pond owner become more knowledgeable and have a successful pond maintenance program.

When people discuss pond water, the most common term used is pH. pH balance is measured on a scale from 1-14 that is based on the concentration of hydrogen ions in the water. A pH of 7 is considered neutral and is the optimal level for a pond and its processes to function optimally. A pH level that is above 7 is considered alkaline and anything below 7 is acidic. The term buffering is used with regards to pH whenever something is introduced into the water that moves the pH from an alkaline level toward the acidic level or vice versa. This can be achieved intentionally through commercial water conditioners or unintentionally through a variety of factors. Some of these contributing factors can be decaying debris and fish waste, fertilizer run-off from grass or nearby fields and even acid rain.

It is these factors above that are usually at the root of most pond problems. Decaying organic matter like grass clippings, dead plants and excess fish food, fish waste and even fertilizer, release nitrogen into the water normally in the form of ammonia, nitrite and nitrate, which can be toxic to fish if the levels get too high. In a biologically balanced pond, the ammonia is turned into nitrite and then eventually nitrate, which is far less toxic and can be used by plants or depleted with a water change.

This decomposing waste, fertilizer and excess fish food also produces a nutrient called phosphate. While phosphate is considered a nutrient and is beneficial to soil, it is not a nutrient that is very beneficial to ponds. In fact, phosphate is the primary culprit behind algae growth. The excess phosphate and nitrogen can quickly cause an algal bloom, which can severely compromise the appearance and the health of a pond.

The primary way that nature combats nitrogen and phosphate is through dissolved oxygen. Dissolved oxygen is the most important factor for a healthy and clean pond. All of the material that falls into a pond that needs to decompose requires oxygen to do so. Dissolved oxygen is also critical for the health of fish, as they require oxygen to process their food. Whenever there is an instance where there are too many fish in a pond or too much decomposing waste, oxygen levels can dramatically drop causing the rise in nitrogen and phosphate leading to fish kills and aggressive algal blooms. It is in these scenarios where oxygenation through aeration is critical, which will be discussed further in the Pond Supplies section.

POND SUPPLIES

There are numerous pond supplies and pond products on the market these days. Some pond supplies are critical, while others are merely aesthetic or can be specific to certain environments like koi ponds or water gardens. However, no matter what type of pond you have, there are some pond supplies that everyone should have in their arsenal for a clean, clear pond.

Aerators
Aeration is key for any pond environment, particularly smaller ponds with lots of fish. As mentioned earlier, fish food and fish waste can lead to increased nitrogen levels, but this is significantly reduced where aeration is provided and dissolved oxygen is introduced to help decay the waste. There are all types of methods of aeration such as fountains, waterfalls, diffused aeration, windmills and paddlewheels.

Fountains and waterfalls are very popular pond products because of the visual appeal they bring. However, their effects can be limited based on pond depth. Typically, fountains and waterfalls are best suited for shallow ponds as they generally only oxygenate the top portion of the water column. Because it is crucial that the fountain or waterfall create lots of turbulence at the surface so that the maximum amount of oxygen can be dissolved, fountains that produce a finer mist of water droplets create more turbulence than big droplets and are a better option.

Diffused aerators are the best option for aerating deep ponds. They use compressors to force air, through tubing, to the bottom of the pond, where it is pushed out and upward. They are also excellent choices for pond owners who prefer less surface movement than what you get from fountains and paddlewheels.

Paddlewheels offer similar advantages and disadvantages as the fountains. They typically are best in shallow water environments and not as efficient in deeper water. They are more efficient than fountains and waterfalls at dissolving oxygen due to the agitation effect from the rotating blades.

Depending on the set-up, windmill aerators can be used to oxygenate shallow or deep ponds. They can be set up to work as a diffused aerator and force air to the bottom of the pond, or they can act like a paddlewheel and turn blades that agitate the surface. Seeing as they are wind powered, their advantages and disadvantages are quite obvious. You will save money on electricity, however you lose your oxygenation on non-windy days, which typically occur in the summer when you need it most. Additionally, they are bulky and hard to install, making moving them unrealistic.

Certainly pond depth is important when deciding on the type of aeration to use, but so is the availability of electricity. Ponds without access to electricity may not be able to support a fountain or diffused aerator or the use of electricity to power an aerator may not be in the budget. Fortunately solar technology is allowing fountains and diffused type aerators to be used where normally not possible. Solar panels are used to generate power to 12 V batteries, which in turn supply power to the units. Solar powered systems are available that operate strictly during day- light hours or during both daylight and night hours.

Filters
Filtration is largely based on the size of the pond and the number of fish that are present. Typically large ponds like farm ponds or commercial ponds do not require filtration because their size makes it possible for them to naturally filter itself. However it is in the smaller ponds like koi ponds, garden ponds or backyard ponds that filtration becomes highly necessary due to the increased concentration of fish and the smaller water volume.

Choosing a filter system can be challenging as there are many types, however, by understanding the activities in the pond water you can better make an informed decision. Below is information on a few types of filters commonly found at pond supply stores.

Biological filtration is a very popular system, particularly among people who have a lot of pond life. Biological filtration utilizes colony forming beneficial bacteria to break down organic waste and convert toxic chemicals like ammonia to less toxic nitrate. Biological filtration systems utilize filter media as a breeding ground for the bacteria to colonize so that when the water passes through the filter, the attached bacteria can clean the water. Filter media for biological filters come in all shapes and sizes, but as long as the media provides a large amount of surface area for the bacteria to colonize on, it will be fine.

Mechanical filters are relatively cheap options and utilize artificial devices or screens to capture floating debris in the pond. They require more manual labor, as they must be cleaned regularly to remove the trapped debris. Fine screen filters capture a greater amount of waste particles, but clog faster. Due to the generally cost effectiveness of mechanical filters, you may opt to use a series of different sized filters to capture more debris and reduce filter clogs. Mechanical filters are more commonly used in water gardens and ornamental ponds where there is limited aquatic life, as they do not provide chemical breakdown like the biological filters

Chemical filtration utilizes activated carbon to remove chlorine, tastes, odors, colors, pesticides, heavy metals and other impurities from the water. This process is called adsorption, where the waste particles adhere to the surface of the carbon. Chemical filtration is more commonly used in aquariums than ponds, however chemical filtration can be effective in a pond to bridge the gap while the biological filter matures.

An ideal pond filtration system should utilize a couple of different filter methods. Normally pond owners combine a mechanical filter with a biological filter to remove the large waste and then biologically break down the toxins for a more complete water filtration system and a healthier pond.

Beneficial Bacteria
Any pond, large or small, can benefit from the addition of pond bacteria. Beneficial pond bacteria are naturally occurring bacteria that break down organic waste in ponds and convert toxic ammonia to nitrite and eventually nitrate. Beneficial pond bacteria are aerobic, meaning they require oxygen, which is another reason proper aeration is very important. You may be asking yourself, “If they occur naturally, why do I need to add more?’

Well, when waste levels get too high, like in fishponds or farm ponds that get lots of debris, fertilizer run-off or livestock waste, it can be hard for aerobic bacteria to keep up and anaerobic bacteria begin to takeover. Once the oxygen levels drop and the anaerobic bacteria become prevalent, waste is more slowly broken down leading to noxious odors and increasingly harmful levels of ammonia and eventually fish kills

Most every retailer of pond supplies will carry multiple brands of pond bacteria additives that can come in many varieties like liquid, powder, packets and even gels. Some people will add the bacteria directly to the filter media to establish a strong colony in the filter, while most people simply add the product directly to the pond, which allow the bacteria to colonize all over the pond and immediately begin breaking down waste.

The only real concern with adding bacteria is that they are very sensitive to pesticides and herbicides, so it is generally recommended that they not be used in conjunction with chemical products within 48 hours of the application of the chemical. Beneficial pond bacteria is also a key component for follow up after an algaecide treatment to break down the dead algae and help prevent further algae growth.

Water Conditioner
Water conditioners or pond conditioners are chemicals added to water to improve its quality, whether it is for the appearance of the pond water or for the health of the inhabitants. For people who have koi ponds, goldfish ponds, garden ponds or other small ponds with aquatic life, conditioning the water is crucial for the health of the fish. In small water environments, minor changes in water volume, waste and other factors as mentioned earlier can compromise the pH balance and consequently the quality of the water.

Pond supply stores carry all sorts of water conditioners, some of which are multi purpose products that can combine dechlorination and pH buffering with ammonia reduction, electrolyte addition, skin slime coat replacement and flocculation providing a wider range of water treatment. While most of these are great products and are excellent for koi ponds and water gardens, there are other water conditioners more appropriate for large, multi acre ponds.

Large, natural pond owners find it more cost effective to buy bulk products like sodium bicarbonate for pH buffering, calcium carbonate (agricultural lime) or calcium sulfate (agricultural gypsum) to settle mud and clay and sodium thiosulfate pentahydrate crystals to dechlorinate when necessary. These farm pond conditioners may not be found at your neighborhood pond supply store, but a call to your local agriculture agent can quickly get you in touch with a supplier.

While the pond supplies mentioned in this section are just a small percentage of the pond supplies out on the market, they are probably the most crucial pond supplies for a pond owner. They are compatible with each other and enhance each other’s benefits, as well as being compatible with most other pond supplies out there.

SEASONAL POND MAINTENANCE

Spring Pond Maintenance
Early spring, while the water temps are still below 50 degrees, is an ideal time to evaluate your pond and make plans for the coming season. This is the time for you to take inventory of your pond supplies and make sure you are stocked up on beneficial bacteria, water conditioners and even decide if there were some new things you wanted to try this year like pond dye or maybebarley straw extract.

You should also check your mechanical systems and your pond structures and plan renovations or additions. For instance, farm pond and commercial pond owners should check their spillways for obstructions and the banks for signs of erosions. If banks are eroding and the spillway is clogged, spring rains can cause big problems. Adding vegetation or laying sod on bare banks can help prevent erosion and limit silting. It is also better to find damaged filters and pumps now rather than in the summer when down time could lead to problems. If you are planning to add aeration, now would be the time to put in a fountain or a waterfall to help oxygenate the water, which will be especially important later in the year.

Spring is also a crucial time for your pond because over winter debris and waste that may have accumulated and, due to low water temps, has not decomposed. All of this accumulated waste will begin to deteriorate all at once as the water temps rise, which can negatively effect the water condition. It is imperative that you have your pond supplies at the ready in the form of beneficial bacteria and water conditioners to help offset the decaying waste. Adding bacteria in the early stages of the season is also good because you are giving the bacteria time to colonize on the filter and all over the pond so that when the fish become active and the associated waste do start to breakdown, the bacteria is prepared to handle it.

Summer Pond Maintenance
The summer months are probably the time when most pond issues arise. Warm weather affects dissolved oxygen levels, encourages algae growth and makes fish more active leading to increased feeding and waste production.

Oxygen, oxygen, oxygen…this should be your mantra in the summer. Whatever aeration device is being used, it is imperative that it is operating efficiently and probably 24 hours a day. Warm water does not retain oxygen as well so you need to constantly pump oxygen back into the water. As noted earlier, increased dissolved oxygen levels will help the pond bacteria thrive and improve the reduction of ammonia, nitrites and nitrate, which fuel algae growth and also help fish digest and convert food to energy.

Speaking of algae, the summer months are when algae blooms become commonplace and increasingly hard to control. All types of debris and fertilizer may find their way into the water, plus fish are more active, leading them to feed more often, causing an influx of nutrients. Additionally, more sunlight is penetrating the water fueling photosynthesis within the algae. Generally speaking, limiting available nutrients, reducing sunlight penetration and keeping oxygen levels high is a good protocol for controlling algae. Below are a few ways to achieve this:

• Continue adding pond bacteria regularly to help consume the problem causing nutrients
• Cut back or remove dead or dying plants
• Plant water lilies or other aquatic plants that can shield the water from the sun and also add oxygen to the water. If plants are not your taste try a pond dye to help filter sunlight.
• Check your equipment like filters and pumps to make sure that everything is working well.

Something else that should be done often, particularly in the warmer months, is a pH check. Because so much biological activity is taking place during this time, pH can drastically fluctuate, but regular checks can make sure you catch these swings and can adjust accordingly.

Fall Pond Maintenance
Inside they call it “spring cleaning”. Outside it is called “fall cleaning”. Fall is when you start to do a lot of cleaning up around the pond and prepping it for the winter months. During the fall ponds can become covered in leaf litter, pine needles and grass clippings, all which can cause problems in a pond. Skimming off dead leaves from the surface of the water along with removing leaves and other debris from around the pond’s edge will go a long way in maintaining the water’s integrity. Obviously, size of the pond will determine if this is practical, but if at all possible it should be done.

You will also want to trim back dead or dying foliage from water plants. This will help with the amount of skimming you will have to do. Along these same lines, if you have any non-hardy plants in your pond, now is the time to re-pot them and move them inside for the duration of the fall and winter.

Because water temps are starting to fall, the amount of food the fish need is reduced, therefore you should reduce the amount of food you feed them. Water temperature affects a fish’s metabolic rate and as water cools, their metabolism slows. If you continue to feed them at the rate you did in the summer, you will create excess waste and bottom sludge or even worse kill them.

Of course, like the rest of the year, continue with your regular beneficial bacteria applications and check your equipment and structures for damage or clogs to ensure everything is operating well.

Winter Pond Maintenance (Pond Winterization)
Based on where you live, the winter months can mean more pond maintenance for some and very little for others. Generally during the winter there is not much to do if you have done the proper maintenance in the fall, as far as cleaning in and around your ponds and checking your equipment. As the water gets cold, the fish require virtually no food, as they are extremely inactive. Additionally, cooler water retains dissolved oxygen better meaning oxygen is not as critical as in the summer. However, in areas where temps get low enough to freeze over a pond, there are some things that need to be done to ensure your pond and its inhabitants survive the winter.

Probably the most important thing to remember is to not let the pond freeze over completely. If the pond surface completely freezes over, then the gases that are produced during decomposition of debris cannot escape and can pollute the water. Also, if the toxic gases cannot get out, then that means oxygen cannot get in, which of course is a problem. An easy solution to this is the use of a de-icer. De-icers are just that, devices used to thaw ice from the surface of a pond. They are not meant to thaw an entire pond, but just a small area so that oxygen transfer can occur. Generally they are placed in the shallow part of the pond. Depending on the size and ice accumulation in a pond, sometimes two de-icers may be needed.

Some people recommend aeration as a means of keeping the pond from freezing over, because moving water, like from a fountain or waterfall, is hard to freeze. The drawback to this is the fact that the aeration unit can cause hyper-cooling, meaning additional cooling of the pond water. If using an aerator in the winter, it is advisable not to use one that pumps air from the bottom of the pond. This can stir sediment causing unnecessary stress on fish, as they tend to stay near the bottom where the water is most warm. It is also recommended that you either insulate or keep the pump indoors so that the water being pumped in will be slightly warmer when pushed back out and will not further cool the water.

During the winter months it is not that crucial to continue with the regular maintenance doses of bacteria, as the bacteria become pretty inactive in the cold water. However, at least one dose throughout the winter can be helpful for the early spring warm-up by giving you a bit of a head start.

SUMMARY

If you are a new pond owner it can seem a little overwhelming thinking about trying to keep that pond clean, clear and healthy. You see all of the pond supplies out there and all of the technical terminology and your head can spin. But, if you just remember to aerate and filter the water, supplement with beneficial bacteria and check the pH regularly to determine if any water conditioners are needed, you will be off to a good start and will find you have given yourself a strong foundation to build on.

Filamentous algae is what you typically see growing on rocks and floating on the surface in mats. It is the stringy, hairlike algae that you often see in the spring and summer months. It has little redeeming value.

Algae in moderation is good for a pond, but when it becomes over abundant, it can cause severe water quality problems. Algae consumes oxygen at night to continue its life cycle, so when there is a severe outbreak, large amounts of oxygen are consumed and can seriously deplete the dissolved oxygen level in a pond to a point that cause fish kills. Not to mention that fact this its flat out unsightly.

What Causes Algae Blooms?

Algae blooms are caused by three factors: excess nutrients, too much sunlight and low oxygen levels.

Nutrients come from a variety of sources, most notable fish and animal waste, fish food and dead/decaying vegetation. Other sources would include fertilizer run-off and run-off from nearby farms and pastures. All of these sources provide much needed nitrogen and phosphorus that algae need to bloom and grow.

Ponds that sit in direct sunlight or have very few aquatic plants are also at risk of suffering from algae problems. This is why generally the most and worst algae problems occur in the summer when the days are longest.

Finally, ponds that experience poor oxygen levels will also suffer from algae control issues. When there are high levels of waste in ponds that are stagnant and still, oxygen levels can be depleted due to the amount of oxygen needed to break down the waste. Algae blooms come and go, but when there is little dissolved oxygen in the water, dying algae will feed new cycles of living algae because there is not enough oxygen to break down the dead vegetation before it can fuel more growth.

First of all, algae should not be looked upon as a problem. It is merely a symptom and a sign that there are other problems and that your pond is out of balance. What it means is that one or more of the causes above are the true problems.

A short term, quick fix is to use an algaecide. However this is just a short term solution because when you simply kill the algae and leave it to degrade on its own, it will just fuel re-growth. A quick kill can also cause an oxygen depletion, which can stress or even kill fish.

The ideal approach for using an algaecide for quick algae control would be to use the algaecide as a pre-cursor to the long-term approach discussed below.

Organic Control of Algae Growth

A more sound and lasting approach would be to control the causes of the algae growth – nutrients, sunlight and oxygen.

Nutrient control involves limiting the amount of nutrients that enter that water that can feed algae. This can range from manually skimming debris and waste from the pond, physically removing the algae, installing an effective filtration system or limiting the number of aquatic inhabitants, but it should always involve the use of beneficial pond bacteria. Pond bacteria is crucial in breaking down and degrading all types of organic waste and should be used regularly.

Reducing sunlight penetration is a more difficult because you only have so much control over that, but a good pond dye and even the addition of aquatic plants can help to shade the water and limit the sun’s effect. A good rule of thumb would be 60%-70% coverage with plants.

Improving the oxygen levels in a pond can be done with a pond aerator or even a pond fountain. The infusion of oxygen will invigorate pond bacteria, making them more efficient at their job, while also keeping the pond water circulating (another deterrent to algae growth).

Effective algae control begins with knowledge and understanding of the type of algae you have and what causes the algae to grow. Once you have armed yourself with the proper information, treating the causes and controlling the sources become more manageable. Then, year after year, preventative maintenance becomes second nature and severe algae blooms become less and less of a concern.