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Beluchting is een belangrijk onderdeel van waterbeheer en -conditionering. Van nature zullen de meeste vijvers, meren en waterplassen jaarlijks twee perioden ondergaan, waarin gelaagdheid (stratificatie) ontstaat. Er ontstaan dan twee verschillende lagen van het water die in elkaar overgaan via een spronglaag of inversielaag (de thermocline). Vanwege de verschillen in dichtheid tussen de lagen, is de onderste laag (het hypolimnion) geïsoleerd van bijna alle invoer van zuurstof, zolang de gelaagdheid aanhoudt.

Voor waterbeheerders is de zomer juist geen periode van achterover leunen. Wat je juist verwacht als waters langdurig bedekt zijn met een ijslaag, gebeurt in snellere en grotere mate in de zomerse maanden. Zonder beluchting, zullen vele vijvers en waterplassen juist dan een zuurstofarm hypolimnion ontwikkelen. De gevolgen variëren van disbalans in het ecosysteem tot uiteindelijk vissterfte.

Door het verstoren van stratificatie van de vijver, wordt het ecosysteem van de vijver voorzien van voldoende zuurstof, waardoor het verstikkende effect dat anders zou hebben plaatsgevonden, wordt opgeheven.

Stank

Beluchting is ook een belangrijk middel om de accumulatie van organische mest dat op de vijver bodem ontstaat, terug te dringen. Onder lage zuurstofgehaltes, vindt ontleding plaats in een veel trager tempo dan onder geoxygeneerde omstandigheden. Daardoor wordt organisch materiaal heel langzaam afgebroken, in feite, meestal langzamer dan de mate waarin nieuw organisch materiaal wordt gemaakt. Het eindresultaat: een vijver die snel steeds ondieper wordt door ophoping van organisch materiaal. Tegelijkertijd borrelen gassen op vanuit de mest en ontstaat de vieze rotte eieren lucht. Goede beluchting is de oplossing.

Beheer voedingsstoffen

Beluchting is ook een hulpmiddel bij het beheer van voedingsstoffen. Onder anaërobe omstandigheden worden fosforverbindingen oplosbaar, waardoor de fosfor kan worden opgenomen door andere organismen (algen). Door een teveel aan planten of algen, kan echter weer een tekort aan koolstofdioxide ontstaan.

Water dat in beweging blijft, zal minder last krijgen van algengroei. Met adequate beluchting en circulatie kun je water continu in beweging houden. Het werkt preventief tegen algen, het doodt dus geen algen. De circulator wordt gebruikt om het water te mengen en te beluchten. Hierdoor ontstaat er meer zuurstof in het water en wordt de afbraak van organisch vuil gestimuleerd. Dit is belangrijk om algengroei tegen te gaan.

Homogeniseren

Een ander voordeel van stroming creëren, is het homogeniseren van het water. Temperatuur, zuurstofconcentratie, maar ook de EC en pH worden overal in het water gelijk en het voorkomt dat er verschillende lagen in het bassin ontstaan met een eigen EC, pH, temperatuur of zuurstofconcentratie. Voor waterbeheerders is dit vooral belangrijk omdat algen ’s zomers goed groeien in de warme bovenlaag van het water. Wanneer de temperatuur in deze laag omlaag wordt gebracht, worden de algen geremd in hun groei.

Blauwalg

Circulatie van stilstaand water in de strijd tegen blauwalg is dan ook een beproefd principe.

Waar gewone, microalgen in stilstaand water uitzakken, maken blauwalgen gebruik van hun vermogen om met luchtblaasjes drijflagen te vormen. Op die manier winnen ze de competitie om licht. Als je door het water te circuleren de blauwalgen naar dieper lagen dwingt, dan verliezen ze de competitie met de onschadelijke microalgen.

Goede beluchting kan zorgen voor aanzienlijke verbeteringen in het ecosysteem van vijvers en waterplassen. Door het circuleren van water wordt stratificatie geëlimineerd. Hogere zuurstofgehaltes resulteren in snellere en gezondere biotische groei van flora en fauna.

Juist in de zomer

We willen wel aantekenen dat beluchting één van de instrumenten is, die nodig zijn voor holistisch water management. Om een evenwichtig ecosysteem te behouden, moeten andere middelen, waaronder gunstige microben en fysieke verwijdering, worden gecombineerd met beluchting. De uitvoering van deze veelzijdige benadering stelt je als beheerder in staat gezond water te creëren en te behouden. De zomer, helemaal als er kans is op onweer, kan een risicovolle periode zijn als het gaat om het zuurstofgehalte.
Daarom verdient het sterke aanbeveling om tijdens zo’n periode zuurstofgebrek in vijvers en meren te voorkomen door pompen, fonteinen, beluchters, diffusers en circulatoren in werking te stellen en te houden. Dit ook en vooral gedurende de nacht.

Juist in de zomer.

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Blauwalg geconstateerd en blauwalg bestrijden? De blauwalg houdt niet van beluchting en waterbeweging. Zie hier de oplossing. Maar hoe werkt dat?

Luchtmengsinstallaties hebben tot doel de plassen in verticale richting te mengen. Hierdoor ontstaat een stroming van het oppervlak naar beneden en weer terug: compressiepompen persen lucht in beluchtingsslangen die op de bodem van de plas liggen. De luchtbellenschermen die zo ontstaan, brengen het water in beweging en zorgen voor stroming in het water. De blauwalgen, die in de bovenste waterlaag voldoende licht hebben om te groeien, worden door de stroming meegevoerd naar het diepe en donkere deel van de plas. Hierdoor worden de algen belemmerd in hun groei en de algenconcentraties in de plas wordt sterk teruggedrongen. Bovendien worden de algen die nog wel aanwezig zijn, verspreid over de waterkolom waardoor ze geen hinderlijke drijflagen meer vormen. Dit systeem is effectief in meren die dieper dan 15 à 20 meter zijn, omdat daar een grote donkere zone aanwezig is waar de groei van de blauwalgen kan worden gehinderd. Maar ook in ondiepere wateren wordt de Kasco apparatuur effectief toegepast.

Meer weten? Bel Kasco: 06-53 346356 of 0181-770 727

Algae? There is hope for your pond, though. Aeration can protect your pond and your fish during an algae bloom and die off. Adding an aeration device, such as a Kasco Pond Aerator or Aerating Fountain will provide added oxygen to the water and help buffer the effect of an algae die off.

When the algae die and are being decomposed, the added oxygen allows the decomposition process to occur properly and also provide oxygen for the fish and other aquatic organisms. By splashing the water in the air, the aeration device is not only adding valuable oxygen, it is also helping to vent gases such as carbon dioxide which is being produced in large amounts from the decomposition process.

Using a Pond Aerator or Aerating Fountain will also help prevent an algae bloom in the first place if it is installed before there is a major problem. As discussed above, the added oxygen will help the decomposition process and actually make that process occur quicker. It will also vent the extra carbon dioxide. This means there will be less available for the algae to use, which is one of the key components to blue-green algae problems.

Adding a Kasco Pond Aerator, Aerating Fountain, or Water Circulator will also create surface agitation in the pond or body of water. This is beneficial in a few ways. First, it helps eliminate the still stagnant water areas and mimics natural wind. As stated above, algae and algae blooms typically occur in the hot, calm, sunny times of the year. The agitation at the surface that eliminates the stagnant areas decreases the areas algae have available to them to thrive. Just simple movement of the water will help limit the amount of algae present in the pond. Just think, when’s the last time you’ve seen a lake that always has ripples or a river covered with algae? Algae do not like moving water or surface agitation.

Surface agitation is also beneficial because it helps to mix up the algae that is already present within the water column. Algae is not able to sit at the surface of the water and soak up all the sunlight it needs for photosynthesis and it cannot survive without large amounts of sunlight. The agitation also helps to destratify the pond by mixing up the water and limiting the negative effects of turnover. With water that has been thermally destratified, the pond is now more hospitable for desired plants and algae species and creates a better pond ecosystem.

Aeration can cause a shift in the carbon dioxide levels within the pond and, in turn, can shift the pH levels causing conditions that are more favorable for desirable algae to out compete the undesirable blue green algae.

Finally, the agitation helps refract some of the sunlight that hits the surface of the water. This limits the amount of sunlight that can penetrate the water column. With less sunlight throughout the water column, algae and other aquatic plants struggle to survive. Some will still linger, but it will help limit the overpopulation of algae and other aquatic plants.

Aeration should not be viewed as a panacea, or silver bullet, but more as one of the many tools typically used in combination with other methods of algae control. Added aeration can never hurt a pond (unless start up of an aerator causes turnover) and most of the time there will be some type of water quality benefit of added oxygen, not to mention the increased oxygen levels are great for your fish.

Adding a Kasco pond aeration, aeration fountain or water circulation pump will help add oxygen and surface agitation to your pond or body of water and will help with algae problems. However, air conditioning and water movement is not cure-all or silver bullets for algae or water quality problems. As with many things in life, it’s all about balance and working with other items that yield the best results. There are several available methods for the prevention and algae, such as herbicides, bacteria and microbes, chemicals, UV sterilizers, and other additives, such as barley straw.

Each has a slightly different way of attacking algae and some may work better in different situations and applications. However, each is designed to help eliminate and prevent algae from growing. Some only treat one generation of algae blooms, others may work for a longer period of time. Either way, when the algae dies off from natural causes or from one of the above treatment methods, there will be a large oxygen demand and Kasco Aeration can help. Also, the added water movement and mixing helps evenly distribute the treatments used and often makes the treatment work more effectively.

Dyes : This is old technology but it can work. Dyes are available in blue or black, powder or liquid, and act to shade water and reduce sunlight penetration that feeds algae growth. Aquashade® is the only EPA registered product for weed and algae prevention, but most other products work, the just do not have the EPA registration. A side benefit that has been explored with some success is tinting the water blue or black to keep predacious birds from harvesting the fish in your pond because the birds cannot see the fish as easy. Aeration works great with dyes because it helps mix up the water and evenly distribute the dye that is added to the water. This method of treatment does not work well in ponds that are pumped from for purposes like irrigation or overflow into other ponds, because the dyes are removed during this process.

Bacteria and Enzymes : This is a non-chemical approach which basically involves living organisms feeding off of the excess nutrients that would otherwise be available for plant growth. Typically they are a concentrated blend of naturally occurring bacteria and enzymes that rapidly biodegrade sludge, improve water quality, decrease suspended particulate matter and solids, and control odor if used correctly in the proper blend for the pond. Many different products boasting fantastic results are out there for consumers. What is critical to the success of using this approach are a few basic guidelines:

1. Bacteria are living organisms and if you use them in conjunction with herbicides there is a good chance they will prove to be marginally successful at best.
2. Dissolved oxygen levels must be at least 2 ppm for effective aerobic activity.
3. As the temperature drops, so does the effectiveness.
4. pH range of most products is 5.5 to 8.5.

 Ultraviolet Sterilizers : This product basically works by using a wavelength of light that will zap planktonic algae. It is very effective for green water, but will do nothing for filamentous or erect algae forms because they will not pass through the unit to be exposed to the light. It should be viewed as a fairly effective approach for watergardens and fairly small ponds, but not that effective for larger ponds because of the costs associated with the larger scale units and applications. Flow rates are readily available from any of the major manufacturers of this type of equipment and are measured by micro watts per second per centimeter squared.

Ultrasonic Sound Waves : The basic science behind these units is fairly sound. They use resonance of ultrasonic waves to kill algae. A submersed transducer generates ultrasonic waves that shock the algae and kill the algae by tearing the gas vacuole which allows them to float. This type of product should not harm your fish. The problem with this approach is that the cost for the unit is high and the results are highly variable and marginally successful at best. The biggest reason behind this is each pond should be looked at almost as a separate organism with varying water quality. A unit should then be sized for those conditions. The problem is that this type of approach does not lend itself to an off the shelf type of sale and more importantly, drives the cost up to the point where it is not feasible for many to spend that type of money on a product without knowing the chances of success.

Barley Straw : Barley straw has been used as a natural alternative to algaecides for centuries throughout England and Scotland. If it is to be sold as an algaecide here in the US, it must have an EPA registration number. Research has suggested that barley straw can aid in balancing the water quality by lowering the pH and carbonate hardness of the water, which can control the growth rate of certain undesirable plants and algae. As the straw degrades in the presence of water and sunlight, it creates peroxide, which can kill both filamentous and planktonic algae. It is better at deterring algae than controlling it once there is already a problem. Application rates area all over the board and success varies from pond to pond. A commonly recommended dosage for private ponds (this is how many get around the EPA registration problem) is 225 pounds of barley straw per acre of water (about 5 bales) in relatively shallow ponds of 4-5 feet deep. It is critical that the barley is loosely packed and that it gets some type of water circulation through the bales. Kasco aeration and circulation products can add this water movement and circulation needed for better success. The bales can also act as a substrate for beneficial bacteria to adhere to and grow. There are also several products, such as barley straw pellets and barley straw extract that can be added to your pond instead of the actually bales, but these products are more expensive.

Skimmers : There are several types of skimmers available on the market. Skimmers are usually not feasible in larger ponds or lakes, but work well in small applications such as watergardens. There are several manufacturers on the market that make skimmers as part of their pond kits that include filters, liners, pumps, etc. to create a watergarden. The skimmer collects water and floating plants and sends them through the attached filter. The filter takes out the plant material and returns the clean water.

Fish : Sterile grass carp have been used to effectively eliminate weeds within many ponds. Contrary to popular believe, they do not like to eat filamentous algae or any other types of algae. They are mentioned here because sometimes they are the cause of a species shift from rooted aquatic plants to a filamentous and planktonic algae dominated pond. The easiest way to understand this is to assume that the fish eat the plants, excrete the waste back into the pond and algae form as a result. The nitrogen and phosphorus that was in the rooted plants has not been removed and will manifest itself in algae, which are not desired by these fish. The questions is , do you want rooted plants or algae in your pond? Grass carp are not legal in every state so consult your regulatory agencies prior to stocking them.

Copper : Copper is usually the first answer most people get when they bring up the subject of algae control. Copper is toxic to certain species of fish within the minnow family as well as salmonids depending on the dosage and water chemistry. Water with high hardness and alkalinity buffers copper from being toxic, but also limits its effectiveness. The most common form of commercially available copper is granular copper sulfate. Its effectiveness and cost as a broad spectrum controller of planktonic and filamentous algae has led to its high usage. Liquid chelated copper products are used to control a broad range of algae including planktonic, filamentous, and bottom attached types of algae. Cutrine-Plus® is an example with application rates from 0.6 to 1.2 gallons per acre-foot of water treated. Consistent usage of some copper products can lead to bioaccumulation within the sediments and this approach is on the radar of some regulatory agencies, so a varied approach is probably the most sensible path to take.

Tilapia have been used to control blue green and filamentous algae in ponds, but they are a tropical fish and will start to “stress” when water temperatures drop into the 50’s. They are also not legal in every state and they are what they eat so there is a tendency for them to be off flavor if they are consuming a fair amount of plant material as a decent portion of their diet.

Reward® : This product is a diquat based, powerful herbicide/algaecide commonly used in natural ponds. It is safe to use according to the label for all types of algae control in natural ponds, but restrictions concerning fish harvest apply. This type of treatment works well with aeration to combat the negative effects of the algae die off.

Physically Removing Algae : This method is used for filamentous algae and erect algae and is very labor intensive. The benefit to this approach is that you remove nutrients with the plants which gets the fertilizers out of the water to temporarily stop the cycle of growth. People have used dip nets, rakes, pulled by hand, etc. Whatever works or whoever works because you will not have people lining up to pull out your algae. The “Algae Monster” at the top of the page has pulled out a few pounds of filamentous algae in his day.

Peroxides : Granular based peroxides are super fast acting contact algaecides for string algae and have been EPA approved within the last few years. Green Clean® is one of these products that has organic approval. It is fast acting and bubbles as it oxidizes similar to medical grade hydrogen peroxide. They byproduct is oxygen and it is safe for fish at the recommended dosages. The remaining filaments and cellulose must be taken out of the water or it will settle back to the bottom of the pond. It is a bit more expensive than some of the other products, but is amazing for spot treatment and does not leave any harmful residues. Application rates vary greatly so it is important to follow the label instructions. As a side benefit, it works well at cleaning algae off of tanks, aerators, sidewalks, and even roofs. This type of control method works well in small applications such as watergardens.

Binders : Aluminum Sulphate (Alum) and forms of alum have been used to clear up muddy or cloudy water and remove phosphorus. Barraclear® is a fairly new product with active ingredients of alum, bentonite clay, and a buffering agent to prevent pH change. It is not an algaecide or herbicide, but it binds phosphorus to starve the plants. The amount required is dependant on the phosphorus levels within your pond so it would be a good idea to get a phosphorus test kit and consult the label for application rates.