Large Ponds

Pond Weed Control And Treatments

There are many things that can grow in a large pond or lake. Algae is one of the more common things you’ll find but along with that, or in place of it, a pond weed will take root and sometimes take over a pond or water way. Some of these aquatic weeds can be very invasive and the more well established they become the harder they can be to control. In this article we’ll talk about some of the more common pond weeds one might find across North America and we’ll provide some tips on the best ways to control them.

Cattails And Emergent Plants

By definition, emergent plants grow mostly around a pond, in shallow waters or along the shoreline. For most of us around the U.S. the most common of these would be cattails, reeds, Pennywort, or Bulrush. Because they are usually within easy reach, many people try to remove these manually by using a pond weed rake, or with some heavy equipment and often enough this can help keep them in check for a time.

If a pond owner is unable to physically remove the plants then an aquatic herbicide is likely the best option, and this generally goes for any type of aquatic weed as well. Remove them if you can, treatment if you must. A product called Shore Klear, combined with an activator such as Cide Kick is usually recommended to treat emergent plants. Shore Klear is sprayed directly on the plant and is only good for those that extend above the water’s surface. It doesn’t work well with submerged growth, however it is highly targetable and works well on many emergent pond weeds.

The Pondweed Familly

The term “pondweed” actually represents a species of plants that has over a dozen varieties of pond weeds that can be found in large ponds. A few of the more common plants include Curly Leaf, Large Leaf, Clasping Leaf, and Sago. It’s not as critical to determine the variety since treatments are consistent within the entire family. You’ll know you have a pondweed species when you see fairly long, vine like stems, with leaves branching off of them at different spots. Most leaves are long and slender however this can vary a bit. Sago as an example doesn’t have leaves to speak of, and you may only see very small vine extensions coming off the main stem. This type of plant can sometimes grow in water as deep as ten feet if it is pretty clear and you’ll often see it extending to the surface where it will spread out.

Several broad spectrum aquatic herbicides will work well on pondweeds. Aquathol Super K and Hydrothol are both granular products that can be broadcast over the plant growth and will usually work well to control growth.

Duckweed And Watermeal

Duckweed is one of the more obvious pond weeds since it only floats on the surface of a pond. It’s fast growing and can overtake a large body of water pretty quickly. Free-floating blooms of it will be blown by the wind and may move around the surface of the pond. If you look at duckweed closely you’ll see a somewhat flat, pod-like pellet that has several hair like roots coming off of it. In great numbers they may appear to be a solid mass on the water but they are in fact, individual plants that are pulling their nutrient support directly from the water.

A pond may go without having any issues with duckweed for many years, however the plant can come in, while attached to waterfowl and when conditions are right it will bloom, seemingly out of nowhere.

Watermeal is similar to duckweed however in appearance it’s much smaller in size with what appears to be very fine green grains however once again, when these are dense enough they will cover the surface of a pond.

Physical removal of duckweed is sometimes possible but usually the best course to take is to use some type of herbicide to control the plant. These should ideally be applied early on in the growth, before it becomes widespread on a pond. A product called Sonar, which contains a chemical called fluridone is usually suggested for duckweed control. White Cap is another brand. For a more eco-friendly option a new product on the market called Elemna8 may provide desirable results as well.

Waterlilies Are Good But…

Waterlilies add beauty to any pond that they grow in. No question about that. They also can help provide shade and protection for fish, and work to outcompete unwanted plants like algae. However waterlilies are also really good at growing and they can overtake a pond if they are not managed somewhat.

If you find that waterlilies are getting the upper hand there are several things you can do. Manual removal is an option if they’re not too heavy. Apart from that a product called Navigate can be applied to control them. After blossoms have appeared Shore Klear can be used to good effect.

Invasive Plants Include Hydrilla And Water Hyacinth

Of all the pond weeds that may cause problems for larger ponds, there are several that are so invasive, fast growing, and prolific, that they are now creating a number of issues in various states around the country. Water Hyacinth (Eichornia crasipes) for example is a plant that’s actually native to South America. It’s actually a popular plant to add to small ponds and water gardens, however it infested freshwater areas from the east cost to the west coast and is very troublesome in the southeast U.S. in particular. In many cases a non-native species can harm desirable local species as it chokes them out over time.

Other waters which may be used for irrigation or cooling can become infested and clog up systems or in the case of Hydrilla in Texas, some lakes there have become so heavily burdened that recreation and navigation are being restricted.

It doesn’t take much of the plant to get a foothold and since conditions are often ideal in the southern United States, the plants can grow and spread very quickly. Some control measures include various herbicides but there are also trials underway using biocontrols. M. scutellaris is a small bug native to South American that feeds very specifically on water hyacinth and they may provide a non-chemical way to keep the plants in check.

Where invasive plants are concerned, the best option is to limit their spread by simply not introducing them into the area’s water ecosystem. Small pond and aquarium owners who may benefit from the plant need to make sure they are disposed of properly. If they are removed from the pond or tank, be sure they are dead for about two days before disposing or insure that they come nowhere near a water source of any kind. It has shown the ability to survive in water in trash cans or buckets. They should never be dumped live into a a nearby lake or stream as they wil likely infect the water in short order.

Pond Weed Control Tips

Along with the recommendations that we’ve included for various plants, as a general rule it’s best to attempt the treatment of many pond weeds as early as possible in the growing season. Most species don’t grow well in cold or cooler weather and in many parts of the country that may freeze in the winter, the plants will go away entirely only to return again in the spring. Treating as the plant is just emerging will often allow less use of any chemicals simply because the plant may be more isolated, and they tend to be weaker at that time as well. This also tends to be much safer for fish populations because during any treatment where a rapid die off of plants occur there is the chance of oxygen depletion in the water.

It’s also important to clearly identify what the plant is that you have growing in your pond. Ideally you don’t want to guess and just simply start trying to treat it. Many species require specific types of products for the best control. The University of Florida offers a helpful website for aquatic plant identification as does Texas A & M University. Use these resources if you’re not absolutely sure of what you have growing in your pond or lake.

Windmill Aeration For Ponds

by Mark

Large ponds benefit tremendously from aeration simply because nothing will do more to increase oxygen levels and circulation in the water. This greatly improves the health and natural vitality of a pond and it can protect and provide an improved home for fish and other wildlife. Pond aeration systems normally run on electrical power which can limit the places where they can be installed. Or it used to be that way. Windmill aeration kits are changing that.

It’s funny in a way that some windmill aerators are thought of as something new. If you travel around the midwest, it’s not uncommon to see old farmsteads that still have windmills standing nearby. Most are not operational any longer but in the old days this was the way fresh water could be pumped to the surface for people and for livestock.

This same technology is now being used to generate electrical power to homes an industry and as of this writing. Texas and Iowa lead the way in wind power generation.

Today’s windmill aerators for ponds also use the power of the wind to drive a compressor pump which forces air through an airline, down to a diffuser which sits at the bottom of the pond. This is very conventional in terms of how it works, and what it does for a pond system, and the only difference between a windmill aerator and an electrical one is the power source. Actually we should clarify that and say, it’s not the only difference but it is the primary one.

Beyond that it’s also important to understand that because of this power source there are other differences that should be compared to decided whether a windmill aerator is right for your pond.

Modern windmill and pump technology has closed the gap on wind driven and electric powered aerators. One of the top windmill aerators on the market today is being constructed by Outdoor Water Solutions and their windmill system will produce about 3.0 to 4.5 CFM (cubic foot per minute of airflow) and is very comparable to a 1/4 HP electrical compressor. This output of course is based on adequate wind speeds. This is the one primary difference between wind driven systems and electric or solar powered aerators. The wind must be blowing for it to work at all.

Due to improved aerodynamics of the fan blades, efficiency has improved quite a bit and even the lightest winds will provide some degree of aeration. Most of the windmill aeration kits that you’ll find on the market can be erected to stand somewhere between 12′ and 25′ which also helps expose the windmill to air currents.

The Windmill Aeration Compressor System

The vast majority of windmill aeration kits that are sold today use a diaphragm pump or compressor. These have the potential output of something like 30 psi which allows them to be used at depths up to about 50′ and they tend to provide a very reliable output of air and performance. For windmills you’ll find two different diaphragms available. These are termed single or double diaphragm compressors. The single diaphragm will produce a shot of air with every full turn of a fan unit where a double diaphragm provides air with every half turn of the windmill. For obviously reasons, the double diaphragm system will provide higher CFM and output and is generally more desirable.

The diaphragm component is usually made of a flexible rubber membrane which is attached to a push plate. Because this is the primary “active” part of the compression system it is most likely to wear out eventually and may need to be replaced. Replacement kits are widely available and are easy to install for the most part.

Output of the windmill systems today usually produce somewhere between 1.5 to 3.2 CFM. This output will of course be based on wind speeds but also the size and design of the fan as well. Larger bladed fans will usually produce better output.

Support structures for the windmills can be found in three leg, four leg, and single pole configurations. Some of the single pole models can be easily erected or lowered through a telescopic feature which can make repair work quick and easy. Most models use a metal beams for the base, however a more rustic wood frame was introduced recently which some people might prefer.

Windmill Aerator Costs And Features

If there were one main redeeming feature of windmill aerators it would be that they will generally offer a continual benefit with a one time cost. For their output, they are much more efficient and powerful than most solar powered aerators at the moment, and there are no additional costs for electricity. Most electrical systems will cost somewhere from $10 to $30 per month to operate so this becomes an immediate savings on windmill systems.

Purchasing costs are similar between the two systems with a single diffuser package costing around $995 to $1,395 depending on the brand and model. In most cases as you add diffusers or need a larger unit, the costs will go higher because of that demand.

All of the models of windmill aerators today with descriptive and helpful user and installation manuals. It’s important to follow the manufacturers recommendations closely to ensure the proper set up and operation of the aeration system. Some of the more popular brands of windmill aerators include the OWS line, Koenders, Superior, and American Eagle windmills.

Duckweed And Watermeal Treatments

by Mark

Duckweed is one of those pesky aquatic weeds that can be very hard to control once it get’s up to speed in a large pond. It’s fast growing, durable, and often not controlled by just any old aquatic herbicide or treatment. In this article we want to explore duckweed in more detail and help a pond owner accurately identify it and offer treatment options which may be helpful in keeping it from taking over a pond.

Duckweed Identification

Common Duckweed (Lemna minor) is an aquatic plant that’s sometimes confused with algae. However it’s very identifiable and quite different in appearance that most algae. Duckweed looks like very small, bright green beads or pellets that appear somewhat flattened. You would find several small “roots” extending from the main body of the plant. Duckweed colonizes in masses and will float freely atop the surface of the pond. It’s usually found in very still or stagnant water in pond with ample nutrients to feed it.

As the name implies, duckweed is often transported from pond to pond by waterfall and they often like to eat the plant. In very limited amounts, duckweed, or it’s smaller relative, watermeal, will not pose any problems but when conditions are supportive of it, the plant can grow rapidly and soon cover the entire surface of a pond. Usually it’s best to avoid this if possible because there is a risk of oxygen depletion in the pond is higher. This of course is not good for fish stocks. Having aeration running in a pond will help guard against this issue but it also may be advisable to try and control the duckweed growth before it overtakes the pond.

Duckweed Control Options

Several viable options exist for controlling duckweed in farm ponds and large bodies of water. Choosing a particular method would depend primarily on the size of the pond, the budget a person might be working with, or a person’s personal philosophy as to whether they would choose to use chemical herbicides or take a more eco-friendly route.

Editor’s Note: It’s usually suggested to treat any pond weed as early as possible in it’s growth cycle to get the best results. If a plant growth is well underway, there is a greater chance of oxygen depletion as it dies off following treatment.

One of the most environmentally friendly options for removing duckweed from a pond is to use some type of skimmer which can manually remove the plant from the water. Since duckweed floats well, it is possible to skim most it off and transport it away from the pond. This offers a chemical free and inexpensive method of control, although it may not always eradicate the plant completely from the pond. To get more information on a useful design watch this video on duckweed skimmers.

Other mechanical skimming options exist that are more advanced than a simple rope, however many of these systems are quite expensive and would likely only be a viable tool for pond management companies to use.

In recent years, one of the more popular and widespread treatments for duckweed is Fluridone. This chemical comes in several brand names such as Sonar and White Cap. This concentrated liquid is relatively expensive but about 8 oz of product (at just under $200 retail price) will treat up to a surface area of 1/4 acre. Fluridone inhibits the plant’s ability to produce carotene and limits it’s production of chlorophyll.

Under normal circumstances it’s recommended to treat the entire pond surface and not spot treat with the herbicide. Once treated, usually the plant will die off over several weeks time and one shouldn’t see any regrowth for the remainder of the season.

Up until recently, Sonar and a few other herbicides were about the only solutions for treating duckweed. In some instances, the use of beneficial bacteria has helped keep duckweed under control, but only if the plant has not progressed to covering the pond. Once it’s well underway, most people had to resort to one of the methods mentioned above, or they would simply leave it alone. Once cool weather arrives the plant will naturally die off and disappear.

In the last year or so however a new, organic and non-chemical solution has been developed which is showing great promise with duckweed control. The product is called eLemna8 and it contains various organic products including turpin oil and concentrated enzymes. What’s interesting about eLemna8 is that it effectively helps to dissolve the protective wax coating which is found on the duckweed petal. It then makes the plant vulnerable and it will begin to die off slowly as the enzyme component begins to break the plant down. The process can be sped up by combining eLemna8 with a herbicide, however the amount of chemical necessary for control is usually much less than if it were used alone. After the duckweed has been killed, it’s not a bad idea to add some beneficial bacteria to the pond to help speed up it’s breakdown completely.

So despite it’s natural durability and propensity for growth, duckweed is a plant that can be effectively controlled in various ways. As noted above, and regardless of what method you may choose to use, the best advice is to treat it early, before it has a chance to take over the surface of a pond. Doing so will allow you to treat it safely in regards to maintaining fish health, and you’ll have an easier time at keeping in check with less chemical use and/or manual effort on your part.

Pond And Lake Restoration

by Mark

What happens when a pond get’s “old and is dying”? What can be done to save it or restore it back to what it once was?

Todays Q & A comes to us from Janet that sent us a link to an interesting article from Sag Harbor News. It seems that Mill Pond, an old and well established lake in the NE United States is in very bad shape. You can read more about this unfortunate situation through this news report.

Answer: Thank you for the link and for your question Janet. It’s inevitable that every pond will age and unfortunately part of that process is a natural “filling in” of the pond basin with all kinds of things. Sediment, blown in debris, shore erosion, the growth and die-off of plants like algae and aquatic weeds, organic material like leaves…they all add up to a pond that is in a state of degradation.

As I’ve often told many large pond owners, the number one goal that you have is to slow this filling in down as much as possible. Some of this may come from proper design considerations but even with this, nature will run it’s course.

Organic build up at the bottom will eventually lead to very high nutrient loading in the water, and like any decaying material, it will serve to create a nutrient density (high phosphates are one component) that is sure to help other aquatic plants grow prolifically. Nutrient spikes can also come from run off from highly fertilized ground around the pond. Algae blooms are fed by these things, and as algae is killed or dies off, it too will add to the organic build up. Nature has a way of dealing this mucky build up, namely naturally occurring beneficial bacteria. But if conditions don’t exist for this to be optimized, then the biological activity simply can’t keep up and the pond keeps filling in at an accelerated rate.

I personally don’t know the history, or the size of Mill Pond but in most cases, you would want to optimize the restoration capabilities of the pond itself. Dissolved oxygen levels should be checked at various points in the pond to make sure they are adequate to support aerobic bacteria. This is particularly important near the bottom where oxygen levels are normally lower. If the readings show a deficiency then some form of bottom based aeration should be installed to improve the condition if it’s feasible to do so.

Along with that, you’ll find that mineral supplementation was mentioned. Interestingly, if a pond has very soft water with low mineral content, and in particular low calcium levels, the natural bacteria will not have the raw material needed to bind to the phosphates and neutralize them.

If algae is a continual problem, chemicals should not be used to control it. Most algaecides contain some level of copper which although it’s toxic to algae, it’s also detrimental to good bacteria, and this is essential to maintain as it’s really the most powerful pond restoration device that’s available. For immediate, non-chemical algae control, it might be possible to limit it’s growth with the bacteria and aeration alone, however if more help is needed, new technology like ultrasound may also be useful to test out.

As the article states, this approach has never been a quick fix to a problem that has developed over many years, however it is the best hope for the pond to be restored to a healthier condition. The good news is that if the proper resources are available and some consistency is applied in the management of the pond, there is ample evidence that the pond can be afforded a new life as a cleaner and clearer body of water.

Winter Aeration Tips For Large Ponds

by Mark

In todays Q & A Of The Day a question came in from Holly who’s using an aerator in her pond throughout the winter. It seems that the compressor running this system is making some odd noises. Almost like an exhalation of air every 5 to 10 seconds and it just started a week or so ago. The system has been running great for months and this is unusual.

Answer: Thanks for the question and email Holly. While your situation with the aerator is not normal in the sense of the word, it may not be unusual at all. This reaction by the compressor represents some form of blocking or kinking in the airline and the added back pressure is being released from time to time by the compressor system.

Since it’s winter, it’s most likely some type of ice build up rather than a kink in the airline. Some condensation can form in the line form time to time an may freeze a bit. To remedy the situation it’s recommended to pour 1-2 tablespoons of isopropyl alcohol into the airline and let it melt what’s in there. Most likely this will open things up again.

Most of the aeration packages you’ll find today are very simple to operate and require very little maintenance. Compressors are designed to run continuously for years with trouble free service and most of them certainly do. This doesn’t mean you won’t run into problems with the from time to time, and the obvious signs of problems usually show up as a change in the sound coming from the device (usually you should hear a light humming) or a drop in air volume being pushed through the diffuser. Should either of these things change it’s probably a good idea to contact the retailer or supplier that you bought the unit from to get some ideas on what to do. If needed, repair kits are available for some models.

Since we’re talking about winter aeration in this article I wanted to remind you of a few suggestions that may help get better results in your pond. Unlike summer aeration, where oxygen is often lower in the pond water, and for best results you would place the aerator diffuser in the deepest part of the pond, in winter you actually want to move the diffuser to shallower water.

The primary reason most people use an aerator in the winter is to keep a segment of the ice open so that oxygen can be exchanged into the pond and any gases, including some toxic ones, can be released into the air. This process get’s restricted when ice covers a pond entirely. An aerator often has the power, through the release of air bubbles, to keep a part of the surface ice free and they can do so fairly affordably.

If you have a multi diffuser system, it’s often fine to just use one of them during the winter and turn the others off. The same benefit can be gained from one, rather than all of them.

Most pond owners find aerators to be relatively trouble free, and particularly when they’re compared to surface fountains. Fountains, as you may recall, pull water up from underneath and shoot it into the air. This often draws debris, algae, and other things into the device and it can plug them up. Since an aerator actually pushes air out of the diffuser, and this is coming from a land based pump, you generally won’t run into any problems of clogging and restriction. In really muddy bottom ponds, you may want to ensure that some gunk and debris isn’t covering the system, but it’s often easy enough to pull these up and check things over once a year. If any rubber membrane needs to be replace, those parts are readily available and easy to install.

Ultrasonic Algae Control And It’s Uses

by Mark

If you’re old enough to remember the original Star Trek TV show, it’s not much of a stretch to look at todays cell phones and chuckle a little bit at the similarities. Technology is truly shaping life as we know it today and it has many benefits. Pond owners aren’t immune to the benefits of high tech equipment and in particular, those who own large ponds with algae problems may now have a tool that will help.

Ultrasound has found many uses since it’s invention. Many are familiar with it’s medical or dental applications, but did you know that pond algae can be affected as well? It’s true. Ultrasonic algae control is, in some cases, replacing the use of chemical algaecides in an effective and eco-friendly way.

Ultrasonic systems work by using a transducer that’s placed in the water. This component is submerged slightly below the surface and continuously sends out an ultrasound wave which, in effect, creates vibrations in an algae cell. Regardless of what type of algae you’re seeing in a pond, all of them are made up of individual cells. And as these cells become damaged through consistent vibrations, they become disabled or die. In simple terms, this is how ultrasound works.

The technology has been in use for almost a decade now, at least in terms of testing. For the last 5 or 6 years ultrasonic algae control has been used in the U.S. . Like any new application, improvements have been made that improve the performance and effectiveness. It’s important that an ultrasound system uses very precise frequencies. The sounds must match the frequency of an actual algae cell, and the closer they can get to that, the more effective they will be.

It’s estimated that for most algae types, ultrasound will be effective from 70 to 100% of the time. There are algae types that, because of their cellular structure, are more hardy and resistent to the vibrations.

Most green water, or planktonic algae can be affected positively, and many types of string algae can be reduced. Normally, after installation, which is often quite simple using an attached float, the device will remain in the water and running continuously. After several weeks, there should be a noticeable difference in the algae. If a device has been in use for 2 to 3 months or about 90 days, and not gotten results, then it’s most likely due to the type of algae that’s present. In cases like this, ultrasound may have helped to an extent but may need more assistance from other types of treatments such as a short term use of an algaecide.

There are models available to treat most sizes of ponds. In terms of the American made Sonic Solutions models, these range from the ss100 which will treat any pond up to about 100 feet in length, to the ss600 which can be used for very large waters ranging up to about 800 feet.

So how do you know if ultrasound is a viable option for your pond?

First, you may want to test to determine the types of algae that are in your pond. Ultrasonic algae control has been used long enough now to narrow down what it will and won’t work on. The test results can be compared to a database of results and whether ultrasound is worth trying or not.

Trials and rentals are available from some companies and ultimately this is the best way to find out if ultrasound will work. There is nothing quite like putting a unit in a pond to find out how well it will do. Usually these rentals will run about 3 months giving one adequate time to test the effectiveness.

For ultrasound to work, it must have a clear line of sight to affect the algae. Islands or other obstructions in the middle of the pond will affect the performance. Also, the transducer which sits underwater, should not be placed too close to a mud lined bottom. Clearance of about 3 feet or more is helpful for the best effect and reduces the absorbtion of the sounds waves into the mud.

If a pond has harder water in it, calcium and other mineral deposits may routinely form on the transducer head. These should be cleaned periodically with a mixture of warm water and vinegar to ensure optimum performance.

Be sure as well to run the unit continuously once it’s installed. It is the constant bombardment of the sound waves that ultimately affect the algae. And finally, if string algae is the main issue, it is often helpful to use some type of treatment to knock down or kill any algae present, then start the ultrasound system. In other words, it’s best to start with a clean pond and use ultrasound as a deterrent to new growth rather than a treatment for what may be present. Green water can be treated as is without the use of an algaecide.

When these basic tips are kept in mind, ultrasonic algae control has shown very good results in a variety of pond settings and for those who are wanting to cut down on chemical applications or the inherent costs of treating a larger pond, ultrasound may turn out to be a great alternative.