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Frequently Asked Questions Q. Can you help with my monolithic design based on cheap grid power and intensified oxygen demand rates with large horsepower blowers.
A. Maybe, but at PEC we focus on the "cloud aeration" approach using individual distributed power solar aerators. Our float or fixed mount, self-contained, EKBS and G2V-STAR models are capable of supporting 0.1 to 10 cfm medium fine ceramic and fine bubble EPDM membrane diffusers @ 1-15 foot water submergence or any water depth using our floating airlift draft tubes. The result is a distributed power sustainable aeration system with a low total cost of ownership, minimal annual maintenance, and the total elimination of mass system failures deadly to fish populations.
Q. pH, CO2, Alkalinity, and Hardness?
A. Low dissolved oxygen (lack of aeration) is associated with all of the interactions of pH, CO2, Alkalinity, and Hardness in ponds. In extreme cases chemicals may be required in the short term, but aeration improves these interactions in the long term by adding oxygen and mixing while saving you money!
Q. Do higher water temperatures cause fish kills?
A. In the US its not the temperatures that kill the fish! Fish thrive in water temperatures in excess of 100 F and Egyptian Tilapia reproduce well at water temperatures above 106 F. Its the lack of aeration (low dissolved oxygen levels) that kill fish. And even a tiny amount of aeration can save them!
Q. Solar vs. Grid Power?
A. Solar always wins because grid power gets interrupted and fish die in minutes without a (UPS) uninterruptible power supply. Your only UPS choice is spare charged batteries or other petroleum free stored power sources. Its not really a choice though, petro spills are a fish poison thats almost impossible to rectify and diesel/gasoline powered devices should not be used around any ponds.
Q. Is Grid Powered Aeration Cheaper?
A. Monolithic grid power aeration designs are based on massive amounts of available cheap power and will never be able to compete with distributed solar power aeration systems. We don't need any power transmission towers or power lines, transformers, electrical distribution systems, etc. We use 10% of the air hose required by a typical monolithic design. Because we need less air hose, we need less power to get the same amount of air into the water using exactly the same diffusers. And of course, with solar aeration, you don't get a power bill ever.
Q. I want to buy/use my own solar panels/pumps and design/build my own pond aeration system.
A. OK, so understand first, that you can't overate unless you begin to suspend solids and you can't under aerate unless you turn off the aerator! The best method of aeration for water quality improvement is to provide 1 cfm/acre 24/7, Attempting to provided 5 cfm for 5 hours may provide the same amount of total oxygen transferred but it does not provide the same water treatment ability as constant aeration.
Langston University Aquaculture programs demonstrate adequate oxygen and mixing with diffused aeration using 0.8 cfm for 1 surface acre of actively feeding fish ponds 3-10 ft deep. USDA Inks Dam National Fish Hatchery found that 1 cfm /acre using a single solar powered air pump and diffuser, in a 10 foot deep actively feeding fish pond, "found it mixes the entire pond and maintains high and constant oxygen levels."
In comparison, studies on blast pumping large volumes of air into the pond for daylight only hours and then turning it off suspends solids and promotes development of a facultative bacteria, not an aerobic type of bacteria, that uses up the oxygen supply quickly when interrupted (they actually do this on purpose in sewage treatment plants to develop anoxic strains of facultative bacteria for denitrification) . Operating in an interrupt aeration mode can kill fish. Under aerating by start and stop aeration vs. constant aeration produces harmful algae strains, and promotes the growth of anaerobic deadly botulism bacteria dangerous to swimmers and ducks.
Think about it, do you think they actually turn off the aeration in the Chicago or San Diego Aquariums? Would you turn off the aeration in your home aquarium on purpose? Definitely not!
Blast aeration is not equal to aerating for 24 hrs/day to improve water quality. We encourage all solar powered aerator development by offering the professional design links below. However, please note that these designs by others have limitations and may not be suitable for continued outdoor use during storms or winter weather.
Click here for direct links to detailed instructions from the Canadian Environment on building your own solar powered aerator system using a 45 watt diaphragm air pump mounted on a small trailer. This is a high pump maintenance design and is subject to frequent down time whenever a cloud passes overhead.
Or click herefor USDA Inks Dam National Fish Hatchery, 0.25-1 acre hatchery ponds, 35 watt diaphragm air pumps and their solar aerator designs replacement for diesel powered paddle wheels.
Both of these designs work well in good weather and control design costs as low as $2,500 for daylight only operation to +$8,500 for 24-hour aeration. Compare those costs to our PEC solar aerator costs here.
Please note PEC only sells systems and does not offer aerator parts for designs by others.
Q. Does your recommended airflow at 2 lpm (0.1 cfm) per 1/4 acre provide enough oxygen for my pond?
A. Due to the huge expenses involved in conducting full scale ASCE oxygen mass transfer testing on aeration equipment, only a handful of individuals have first hand knowledge of how vertical and horizontal flow developing aerations systems perform. PEC has conducted more than 200 such tests Internationally on ponds, lakes, lagoons, and tanks using splashers, fountains, bubbling diffusers, aspirators, propeller pumps, etc. We have always found, without exception, that all of these systems quickly establish a saturated oxygen "zone of influence" in the immediate area of the aeration device itself. We have also never found a mixing limited situation where any additional energy, beyond the aeration device itself, was needed for some oxygen dispersion throughout a contiguous body of water.
You will find from some aerator manufacturers, whose business is based on sewage treatment, tell you that you need lots of power and lots of high pressure compressed air to adequately aerate a body of water. Sewage water aeration designs are a massive overkill for recreational water treatment designs. Applying more than 1/2 horsepower of aeration per surface acre, 3-10 ft deep, will cause more damage than good to earthen basin recreational ponds. From a recreational and aquacultural design standpoint for pond aeration, USDA fish hatcheries and Canadian Environment studies show that using diffused air at 50 watts per acre foot is adequate for mixing and maintaining the higher oxygen levels needed for fish. As an example, a 190 lb. man needs 3-7 liters per minute of oxygen laden air to stay healthy, 190 lbs of fish need about the same. The manual pedal paddle wheel bicycle aerator, which has been supplying aeration for Asian Aquaculture for a more than a century. It typically provides less than 1 lpm of constant water/air contact(very similar to other grid or solar powered water circulators that develop high velocity laminar flows moving lots of oxygen bearing surface water with little or no turbulence so the layers of water slide like cards over each other with minimal oxygen transfer).
In comparison, PEC diffused air testing and other more in depth studies such as those conducted at a polluted stagnant Reed Swamp shows 30-250 mg/m2/hr per surface acre of oxygen demand. Oxygen demand is the amount of oxygen consumed and you need to apply several times that number to improve water quality. Wind driven normal wave action typically is limited to transferring less than 3 mg/m2/hr. Our EKBS-10 at 0.1 cfm (2 lpm) airflow can supply more than ten times that at 2500 mg/m2/hr of oxygen. Fewer than four EKBS-10 units per surface acre, thats one unit for each 1/4 acre of water, can easily meet this demand. Unless your pond is more polluted than Reed Swamp, an EKBS-10 provides plenty of oxygen for your small pond up to 1/4 acre, using our floating airlift aeration diffusers. If you actually have sewage flowing into your pond, the EPA recommends 0.5-1.0 cfm per thousand gallons of raw sewage. If you find that you have raw sewage flowing into your pond or need more air in the future, its as simple as adding another self-supporting PEC solar aerator. The additional power is still power bill free and unlike grid power, does not require expensive new power handling and distribution equipment.
Q. You offer both "bottom mounted diffusers" and "floating airlift aeration diffusers." Why?
A. Floating airlift aeration diffusers reduce the number of solar panels required and cut capital cost while only slightly reducing oxygen transfer. When using the free energy of the sun, your projected power costs are ZERO so the choice is really "cost of ownership." However, bottom mount diffusers are popular and asthetically pleasing. Here are a few specifics|:
1. Based on EPA studies, deeper placement of diffusers gives you higher oxygen transfer rates. You get a 1-2% increase in "clean water" oxygen transfer rates for every 1 ft. of diffuser submergence. Our airlift aerator has a diffuser at a submergence of 3 ft. If you take a diffuser and place it on the bottom of the pond (10 ft. vs. our floating diffuser at 3 ft), you will see an increase in oxygen transfer as high as 4% with a 400% increase in captial cost (more solar panels). Doesn't make much sense to operate deeper , driving up capital costs, when solar power is free!
2. When you put a diffuser on the bottom of the pond it will take more energy to get the same (or any) airflow. Therefore, you will need to increase the size of the solar array significantly.
3. A diffuser placed on the bottom of a pond will mix and destratify the thermal layers of a pond. The main drawback of bottom placement of diffusers is increased summer and decreased winter temperatures in bottom water stressing the fish and biota. More recent studies now focus on hypolimnetic aeration techniques supporting the use of floating air-lift aeration (draft tubes) as a management strategy to decrease the sediments oxygen demand while preserving thermal stratification zones and reducing stress on the fish and biota.
Q. Where do I place the floating or bottom mounted diffusers in my pond?
A. Placing a diffuser anywhere in the pond increases the oxygen and mixing everywhere in the pond by natural dispersion (higher oxygen around the diffuser and lower oxygen everywhere else). First, the main goal of diffuser placement is to locate it as far away from the overflow or discharge of the pond as possible. Second, place the diffuser(s) equidistant from each other and/or opposite shorelines closest to the inflow or influent water so the natural water currents can disperse oxygen throughout the pond. Last, attempting to add additional lengths of airline or place diffusers deeper than designed reduces aeration efficiency and/or eliminates airflow altogether.
Q. My problem is Algae. The pond used to be beautiful, What happened?
A. You have a build up of nutrients in the pond that needs more dissolved oxygen (aeration), period.
Eutrophication, a process whereby most older ponds and lakes develop excessive nutrients that stimulate excessive plant growth (algae and aquatic plants). Dissolved oxygen concentrations will severely decline when large amounts of algae (algal bloom) and aquatic plants begin to decompose. In turn, very low dissolved oxygen concentrations can cause fish kills.. Nutrients can come from many sources, such as fertilizers applied to agricultural fields, golf courses, suburban lawns, soil erosion, streambank erosion and sewage treatment plant discharges. The symptoms of eutrophication are:
Low Dissolved Oxygen Concentrations
Poor Water Clarity (Transparency)
Algal Blooms (Excessive Amounts of Algae)
Excessive Quantities of Aquatic Plants (Weeds)
High Dissolved Metal Concentrations (Iron & Manganese)
Stress to Fishery and Other Forms of Aquatic Life (Fish Kills)
High ammonia levels >5 mg/l, due to the Accumulation of Sediments
Nutrient Releases via Anoxic In-Lake Sediments
Buildup and Release of Noxious Odors & Toxins
Botulinum toxin (Avian Botulism)is a protein and neurotoxin produced by stagnant anoxic water borne anaerobic bacterium, Clostridium botulinum. It is the most acutely toxic substance known on earth. Sporulation needed to produce the neurotoxin is easily preventable with simple water aeration methods.
Harvesting algae as bio-fuel or fertilizer controls algae. Aeration at any level will also improve the water quality, reduce ammonia levels and decrease the frequency of algae blooms. Most chemical treatments only delay the need for aeration by chemically storing the nutrients as dead algae on the bottom of the pond. A few chemical treatments like www.ALGAEOUT.com work with solar aerators to remove the nutrient levels in the water so nothing is left over for the algae to thrive on. Ammonia levels are easily detectable with aquarium test kits from any fish store. The lowest cost method for removing ammonia is also solar aeration (air stripping). If ammonia levels spike they can be quickly lowered by broadcasting Zeocarbon by hand. Simply apply 10 lbs/acre (10 lb of Zeocarbon at standard temperature and pressure can absorb 2 lbs or >1 mg/l per acre ft. of ammonia) and re-test ammonia levels. Add more Zeocarbon as needed.
Q Our state agency does not encourage use of grid powered aeration or chemical additives and says to stop feeding my fish to prevent kills.
A We agree, somewhat! You need to aerate the pond and stay off the grid while doing it. It is Environmentally undesireable to aerate using power from unsustainable fossil fuel grid powered systems. However, not only is it desireable to use sustainable solar powered aerators to improve water quality, remove nutrients/pollutants, control algae, enhance fish production, and control insect breeding, it is putting Reconciliation Ecology into actual practice.
Q. How much mixing do I need?
A. Published studies demonstrate less than 0.15 cfm of diffused air per surface acre is needed to maintain oxic sediment in a 1 acre pond, 10 feet deep. Ponds are almost never mixing energy limited when you are adding aeration to improve dissolved oxygen levels. Maintain mixing energy under 750 watts/acre and airflow levels under 1 cfm/acre will allow solids to settle and prevent turbid or cloudy water conditions that could block out the sun, stop natural biological processes and destroy the ponds highlife.
Q. How much dissolved oxygen do I need for fish and algae control?
A. You need to maintain the dissolved oxygen in a "fish safe zone" from 3-5 ppm at all times, night and day, to prevent fish kills. In a typical fresh water pond that typically means less than 1 cfm per surface acre for most game fishing ( +6 cfm for trout).
Biologists at Inks Dam Natioanl Fish Hatchery have completed their pilot study and know the optimum size and power requirements for aerating one-acre game fish ponds using solar power. Aeration helps prevent fish kills during the hot Texas summers when dissolved oxygen levels can plummet in ponds. Combining a centered 120-watt photovoltaic panel with a 1/8 horsepower pump and bottom mounted 9-inch disc air diffuser mixes the entire pond and maintains high and constant oxygen levels all summer in Texas.
PEC recommends a minimum of 60 watts per surface acre (2 of our EKBS-15 units) when fish are not being actively fed.
Q. I still want a fountain or a splasher to look at?
A. Both Splashers & Fountains are pretty to look at, but you would have to surround your pond with solar panels to make them work at all. Then you would have to pull weeds off the pumps, filters, and props everyday. Every boater knows you spend an hour cleaning the weeds off the prop on every outing. The maintenance on mechanical splasher/fountain aeration is DAILY. Other than sinking a well and using high pressure well pumps the only no maintenance or "low" maintenance aeration method is diffused aeration (bubblers).
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