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hppondandpatio
Admin
5853 Posts |
 Posted - 03/23/2005 : 08:37:00 AM
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AlGAE
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Filamentous Algae a problem?
I saw a lot of ? regarding string algae etc. This is a blurb from our website and some thoughts from Norm Meck regarding algae, etc.
In early spring your system will contain more string algae than usual. This is because string algae is actively growing before the rest of your system "wakes up". Remember that string algae bothers YOU, NOT the system! This is not a swimming pool, it is a pond. For all practical purposes your rocks will never look like they did right after installation. Simply remove the string alage by hand, twist around a toilet brush or use Ecoblast.
The degree of "problem" is usually concerning aesthetics alone. During teh season a good thin layer of string algae in a rock bottom pond provides a place for fish to camouflage, graze and cool off. Although its appearance may bother you, string algae is considered beneficial to your system and is a sign of good water quality. The key is balance. As string algae reproduces it gives off oxygen which becomes trapped and allows it to float. Simply remove the floating algae from the surface. Mechanical control ecoblast or the addition of snails is all we recommend.
Use Ecoblast for spot treatments, empty skimmer often after using ecoblast as the algae will release and fill your skimmer fairly quick. Do no use Copper Sulfate in Aquascape Systems. SAB can be used after your spring clean out as a preventative.
Be Patient!
If your system is new, understand that it takes between two and six weeks for the bacteria to colonize and actually begin to do thier job. Creating a balanced ecosystem doesn't happen overnight. Like fine wine, ponds mature with age, so don't be surprised or concerned if a new pond begins to grow some algae. Once the plants, fish, and bacteria are established, the algae will decrease.
Yearly Cycles
Most ponds undergo an algae cycle every year. In colder climates, both plants and bacteria will go dormant due to a lack of oxygen in the cold water. This creates less competition for nutrients and advantageous conditions for algae growth. The pond may turn green or become full of string algae in winter. Once the temperatures warm up, the plants and bacteria will begin to establish themselves once again.
Other Causes for Algae - Was your system designed properly?
1.Over stocking/overfeeding - too many fish. Stock at 1" of fish per 20 gallons of water.
2.under circulating - is your pump too small?
3.underfiltering - pump rate and filter size
4.immature pond - as stated above
5.runoff and/or rain - closed systems do not handle unintended input
The Nitrogen Cycle
Koi and decaying organic materials are continually producing ammonia. By converting the produced ammonia NH3 to nitrite NO2 then to nitrate NO3, we can further break the nitrate down to nitrogen gas N2 or nitrous oxide N2O and this can then be gassed off thus completing the nitrogen cycle. The first element produced by carp/Koi is ammonia, Koi cannot be subject to Ammonia in anything other than very low concentrations, over time aerobic bacteria are naturally formed in the filter called Nitrosomas spp. and Nitrobacter spp, These two specific bacteria need only a source of energy,oxygen, and a substrate the rest mother nature will take care of.
Nitrosomas, classed as chemoautotrophic bacteria, are responsible for the conversion of ammonia (NH3 and Nh4+) to Nitrite (NO2). Nitrosomas utilize ammonia as a food source, oxidizing the ammonia to form Nitrite, (NO2). Nitrite in itself is nearly as toxic as ammonia in its newly formed state, but a second colony of bacteria form, again quite naturally, called Nitrobacter spp, they convert the Nitrite to Nitrate (NO3), which is about 1 hundred times less toxic to fish than either ammonia or nitrite.
De-nitrification can take place by another set of bacteria called heterotrophic bacteria. These bacteria require complex organic compounds of nitrogen and carbon for metabolic synthesis, These bacteria can be aerobic or anaerobic, (function in the absence of oxygen) and are capable of conversion of Nitrate NO3 to nitrogen gas (N2) or nitrous oxide (N2O) thus keeping nitrate levels down to a minimum. These bacteria are required in sufficient numbers to make a difference to the background levels of nitrate.
There are also a select number of anaerobic bacteria that will use the oxygen and nitrate to reverse the nitrogen cycle. By removing one oxygen atom at a time it can convert nitrate NO3 back to Nitrite NO2, then back to ammonia NH3/NH4 This is accomplished by anaerobic bacteria usually found in the sludge build up in the bottom of a dirty pond or filter, as the sludge builds, it deprives the bacteria of oxygen and becomes one of the main reasons for a filter crash. This is why a correct install has less than 2 " of gravel on the pond floor. The aggregate provides surface area for colonization. Too much creates unfavorable conditions.
Competition for nutrients - Plants and Ammonia
We know that algae will proliferate when ammonia levels are higher. One of the main foods for algae, both single cell and hair is also nitrate. Plants readily take up and use two forms of N:
ammonium (NH4+) and nitrate (NO3-). Other forms of nitrogen must be converted to one of these compounds by natural or artificial means before plants can utilize them directly as a source of nitrogen for plant growth.
Why is ammonia is easier to break down than nitrites or nitrates?
The ammonium molecule (NH4+) carries a positive electrical charge and is attracted to the clay and/or organic matter arounds the roots, which carry negative charges. I'll call the organic matter around the roots "soil" just for simplification. Once attached to the "soil" matrix, ammonium becomes part of the cation (pronounced "kat-i- n") exchange process whereby plants exchange a hydrogen ion (H+) for one of the positively charged molecules in the "soil".
As long as the temp and the pH are low enough the second that ammonia hits the water it picks up the extra H+, hydrogen ion and becomes ammonium and is useable by plants and algae. NO3- must be reduced to ammonium before it can be incorporated into proteins anyhow. The conversion is catalyzed by enzymes collectively called the nitrate reducatase system. They produce enzymes like glutamine which are then transported throughout the plant. In essence they produce the N containing compounds that can be used in protein synthesis. As we already said since nitrosomas are changing NH4+ to NO3- (nitrification) it is Nitrate that is more abundant, but not preferred. Again since it is not positively charged it is not "bound" . (this is whay we have to fertilize lilies since it is not bound it is "leached" from soil pockets). This reductase process is inducible. Inducible enzymes are common in bacteria but very uncommon in plants. Then of course we get the De-nitrification by the heterotrophs taking NO3 to nitrogen gas (N2) or nitrous oxide (N2O).
Why do we add bacteria?
Decomposing bacteria and the bottled stuff we add are all hetertrophic bacteria. These bacteria use organic, nitrogenous material like plants, debris and dead fish as thier source of food and carbon source. These bacteria can be either anaerobic or aerobic and are capable of producing spores. That's why they can be bottled or dried. As we have said, these organisms conduct a process called aerobic bacterial decomposition but it is more commonly known as decaying or rotting. They consume dead organic matter. Green water is caused by an excessively large number of tiny organisms in the water called phytoplankton. Algae have specific requirements for growth just as any other plant. Competition and removal of requirement sources limit its growth.
"When an algae cell dies (for whatever reason), the cell wall structure can no longer support the osmotic pressure of the water entering the cell and the cell bursts. (I have observed this happen under a microscope and it is similar to a kernel of popcorn popping). The now exposed cytoplasm is quite sticky and has a natural tendency to adhere to anything it might come in contact with. The internal surfaces of the bio-filter media are a natural trapping location for these cells and combined with the oxygen rich water, a healthy environment is provided for the growth of heterotroph bacterial colonies to decompose the dead cells. Although the bacteria prefer to consume the nutrient rich cytoplasm (and almost any other rich organic waste), when that is consumed they will then work on the cell walls. A waste product of the decomposition process of the cell walls is an antibiotic that is toxic to algae. The presence of this antibiotic in the water causes other algae cells to die, the heterotroph bacterial colony increases in size as more "food" becomes available, and as more antibiotic is produced, more algae dies. This continues until an equilibrium point is reached where one of the requirements for the sequence becomes limiting (remember good old Liebig's Law). If the limiting factor is the amount of "food" for the heterotroph bacteria, the water has relatively few remaining algae cells and appears quite clear. If the limiting factor is the amount of space available for the bacterial colonies and the capture of the dead algae (i.e. insufficient amount of filter media) then the water may still have sufficient algae concentration to retain some level of turbidity. This turbidity level (how green it is) will be determined by a combination of all the different characteristics of a given pond and filter system." - Norm Meck http://www.koiclubsandiego.org
What Works and What Doesn't Myths
Shade - Algae needs very little sunlight to grow. Contrary to popular belief providing shade will help stabalize temperature, but has little to no effect on algae short of completely covering your pond. Algae does love warm water though. As mentioned, shade will lower and stablize your temperature.
Flocculants - Often misused, flocculants will help clear water from organic debris including dead algae. It has very little effect on living cells. As some of Norm Mecks research implies the consumption of dead algae cells may contribute to the killing of living cells by the release of an antibiotic. This being the case removing the dead cells may actually inhibit a natural control.
Major water changes - This obviously removes algae, but does nothing to control growth of the remaining algae and it adds nutrients.
Nitrifying bacteria eat the algae - As I mentioned above nitrifying bacteria are chemoautotrophic bacteria, they use only inorganic sources. Nitrosomas convert ammonia to nitrite, Nitrobacter convert the Nitrite to Nitrate.
Algaecide - Most are copper based. Koi and copper are not friends. Quick kills of Algae blooms also use up too much oxygen
Facts
Before I mention what may help please note there is no "snake oil" or magical fix. More often than not your problem is :
1.Over stocking/over feeding - too many fish. Stock at 1" of fish per 20 gallons of water.
2.under circulating - is your pump too small?
3.underfiltering - pump rate and filter size
4.immature pond - as stated above
5.runoff and/or rain - closed systems do not handle unintended input
SAB - String Algae buster is for STRING ALGAE. Use this for prevention. SAB locks up" calcium. Without calcium string algae breaks up. Best control - Use your hands and get in there and take it out! Your fish will be happy to see you. SAB is Temperature Sensitive.
EcoBlast - String algae control. Works by direct contact with the algae. Ecoblast is not temperature sensitive.
Bitty Bales - Decomposition of barley releases peroxides that break down the cell walls of algae. (do not confuse with peroxides with hydrogen peroxide). Again helps more with prevention - not bloom control. Will take 4-6 weeks.
Aquaclearer - increases "competition". Heterotrophs explained above. Aquaclearer does not seed your biofalls, it contains bacteria for organic decomposition.
Bioballs - Lava Rock becomes clogged in one year. Replace with bioballs your second year. Bioballs add more surface are for bacterial colonization and do not clog like lava rock.
Best practices are physical and require your involvement:
Under or properly stock - conservative approach is 1 fish per 250 gallons
Over Circulate - turn over at least every 1 hour
Overfilter - be sure your biomedia is "fit" to the biofall. The water must past by it, not around it.
Time - relax it isn't a swimming pool. Let it balance
Proper cleaning and maintenance
10% water changes regularly
Fall / Spring Cleaning
50-60% plant coverage
cleaning skimmer mats at least biweekly
hand removal of string algae
Testing Water Quality
Ammonia 0ppm
Nitrates under 80ppm
Nitrites 0ppm
Chlorine reading of 0ppm
KH over 80ppm
pH stable between 7 and 9
__________________
Bob
www.pondandpatio.com
www.nawgsmadisonwi.com
Bob Wambach, CAC
HP Pond and Patio, LLC
NAWGS Madison Chapter
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Algae
