Surge devices various methods

Discussion in 'Pumps and Waterflow' started by seank, 21 May 2008.

  1. seank

    seank

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    As you all well know, I have been looking into this type of natural "waterflow" devices for some time. So I thought of posting different "types" of what I could find on the net as to help others to make decisions regarding devices that'll work for them.(and hopefully it will help me understand it better)

    Please feel free to post Original Methods as well as their Write ups in this thread.(maybe have some sort of Competition to see how many different ones, quiet ones, big ones, etc we can post on this thread....:thumbup:)


    Oh, and before I forget, please accompany the posts with detailed pics irt assembly etc...
     
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  3. seank

    seank Thread Starter

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    Carlson Surge Device and its origins:

    The sight was almost mesmerizing. I looked downward into a concrete box some 10 feet square. A water flow rate of perhaps 1,500 gallons per minute rushed into the structure and slowly filled it. When it seemed the box would over flow, a hiss of escaping air drowned any background noise and the water movement became violent as the box quickly emptied. Near the bottom, maybe 10 feet below ground level, were pipes that were exposed briefly before being covered by the incoming water. A slurping noise accompanied the spectacle and added a hint of danger. I stepped back, not wishing to fall into the pit.
    I am describing a scene from an old wastewater treatment plant on the outskirts of Atlanta.
    The plant was demolished years ago but the sight of a device called a "bell and siphon" (or dosing tank) are still vivid. Little did I realize these devices would one day be down-scaled and offer something of interest to the reef aquarium hobbyist.
    Today, the bell-and-siphon for the aquarium is known by several names. One of them is the "Carlson surge device", CSD, for short - named after Dr. Bruce Carlson. He installed one of these devices on a display tank in a public aquarium in Hawaii. At least one manufacturer builds relatively small surge makers for home aquaria.
    If the hobbyist has a few minutes and a few dollars, he can construct a surge maker. I must warn the hobbyist that this thing is not for every aquarium. They are intrusive in appearance. In fact, they're ugly. And like their industrial cousins, they're noisy. But they can create incredible water movement in the aquarium. I recently built and installed two of these things on my six-foot long reef aquarium. I was so impressed with them, I removed a "dump bucket" that had been in service for over 6 years.
    I had attempted to build a surge maker a couple of years ago based on a design shown in a water reclamation reference book commonly known as "The New York Manual". I could not get the device to work and I abandoned the project. I saw a schematic on a very similar device in Delbeek and Sprung's "The Reef Aquarium", but wasn't motivated enough for a second attempt. It wasn't until I saw a surge maker in action at John Lipsey's Shark Bay Aquarium in Atlanta that I was tempted again. John had constructed this deceivingly simple device from just a few parts and installed it on his Acropora tank. When I saw it, I was taken back through the years to the scene at the reclamation plant. I was mesmerized again. I saw in the tank fully expanded Acropora, Stylopora, Porites and other stony corals (see photo). I had to have one (or two). I rushed home and, within minutes, built a prototype. And it did not work. I decided to write this article for two reasons: 1) to assist those interested in good water movement and 2) help those so inclined in avoiding some of the frustration I went through.
    [​IMG] Water movement is often mentioned as a critical factor in success with a reef aquarium. Amazingly enough, most hobbyists believe one or two powerheads produces sufficient water movement. In many cases, especially if the aquarium is small and contains only soft corals, this sort of set up is okay. However, for large colonies of SPS (small polyp stony) corals, this simple arrangement will not create sufficient current and may cause the death of the animals. A surge device is a good addition and may well make the difference between success and failure.
    I will describe building a 5 gallon surge generating device. Certainly, the size can be scaled according to your aquarium's needs. Just be prepared to experiment. Small things that do not appear significant can profoundly affect performance. Discharge pipe size, height above the aquarium, flow rate into the bucket, along with other parameters, may need to be adjusted. I would strongly advise building a prototype or two when scaling this device to size.
    Perhaps the easiest way to deliver water to the bucket is to place a small submersible pump in the aquarium. This way, some of the problems can be avoided. But perhaps the best way is to use a more powerful pump. (I use a MDSC-4 Little Giant pump plumbed into the sump.) This will create a few problems. The scenario is as follows: The pump takes water from the sump and pumps it to the surge bucket. The water level in the sump will fall. When the surge device is full, and discharges, a rush of water enters the aquarium. The aquarium must hold this water as it drains into the sump. If the overflow drain is too small, a real possibility of the aquarium overflowing exists (along with the domino effect, usually in this order - wet carpet, angry wife doctor bill, etc.). The sump must be large enough to hold the influx of water while the pump plays "catchup". The sump must not run dry in order to avoid pump damage. So, the size of the sump is an important consideration and may dictate the size of the surge device.
    These are the parts needed:
    1 - 5 gallon bucket w/lid
    1 - 1 1/2" bulkhead fitting and pipe
    2 - 1/2" fittings and pipe
    1 - 1/2" 90 degree ell
    2 - 1 1/2" 90 degree ells
    1 - 1 1/2" 45 fitting
    Hardware to hang the bucket from the ceiling (Optional- small surge devices may be placed on the top of the aquarium)
    When assembling these parts, be careful to cut the holes far enough from the side of the bucket to allow threading the bulkhead components together. A dab of silicone cement on the bulkhead gaskets will ensure a water-tight seal.
    The drawing shows the dimensions of this 5 gallon surge-generating device.

    [​IMG] The lid will keep water from splashing out of the bucket and will keep dust and other debris from getting into it. It will also dampen the noise of the siphon breaking.
    The overflow is a strongly recommended option. Although these devices seem to be fail-safe, there is little doubt that an overflow could be disastrous. Use a pipe from the bottom of the overflow to the aquarium - but do not submerse the end of the overflow tubing - the object is to allow the bucket to drain. Do not make the overflow work against the head pressure of a submerged tube!
    If the device never breaks siphon, then the hobbyist is advised to examine the flow rate into, and out of, the bucket. Water is either being added at too high a rate or the effluent pipe is not carrying water out of the bucket fast enough. A smaller pump may be needed or the flow can be throttled by an inexpensive ball valve. Of course, a second surge bucket can be added to handle the "extra" flow.
    The hobbyist should be aware that this type of surge bucket (I can't speak for the commercially available models) will add lots of bubbles to the aquarium. Is this really bad? Air bubbles will lessen the amount of light reaching your corals; the bubbles appear bright because they reflect light. The lighting fixture will become coated with salt spray unless it is raised a few inches higher. of course, this lessens the amount of light actually reaching the aquarium. Also, corals and anemones will ingest the air bubbles but apparently no harm is done. On a more positive note, these bubbles will probably strip the water of waste products, just as a protein skimmer does. Overall, the very positive effects of increased water motion will likely outweigh the drawbacks. Note - a small air relief hole may be drilled in the discharge pipe below the water surface. This allows some air to escape before the rush of water follows. Do not drill the hole so it is above the water surface -it will not work!
    The velocity of the water exiting the devices I built is around 4 feet per second. This velocity seems to be the result of the buckets being about 2 feet above the aquarium. (Those closer to the water surface will probably not develop this high velocity.) Once set, this velocity will never change. The pump sending water to the aquarium will age and become less efficient. This will affect only the periodicity of the surge, not the discharge velocity.
    All in all, I strongly encourage the hobbyist to experiment with devices of this sort. I can say they are much more efficient at producing water movement than a "dump bucket". And, in reef aquarium terms, these things are dirt cheap. And they don't take a long time to build either. In other words, there are few excuses for not trying one of these surge devices on your reef tank. If SPS (and other) corals were capable of emotion, they would love you for it.

    [​IMG]
     
  4. seank

    seank Thread Starter

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    How to Build a Powerful Surge Device

    by Dr. Bruce A. Carlson
    Director, Waikiki Aquarium
    Introduction
    When we began keeping acroporid corals in 1985, we believed it would be necessary to provide significant turbulence in the water to simulate the corals' natural environment. Recent research has indicated that turbulent water is indeed vital to the health of these corals as it greatly facilitates the diffusion of nutrients and wastes in and out of the corals. The problem for us was how to develop a device that provided a strong but periodic surge, was inexpensive, and most of all would be maintenance-free. Dump buckets are notoriously troublesome, requiring constant adjustment and repairs. Powerheads are generally too small for big aquariums, and generally unsuitable for use outdoors. Larger pumps provide the necessary output but a continuous flow of water is not good for the corals and does not simulate natural conditions of periodic surge. The best design to meet our criteria was an automatic siphon device which has proven to be reliable and effective, and is inexpensive to build and to operate. Delbeek and Sprung (1994) published a diagram of our surge device, but I have received many requests for more details, hence the publication of this report.
    Before proceeding, I must acknowledge the advice of Dave Powell at the Monterey Bay Aquarium. When we first considered building one of these devices in 1985, Dave gave me a verbal description of a similar system that he installed at the Steinhart Aquarium. Many public aquariums use surge tanks for a variety of applications but we were probably the first to employ one with living corals.
    How It Works
    The accompanying diagram illustrates a 150 gallon aquarium (#4). A Little Giant 3MD pump (#6) draws water from the aquarium through a 3/4" PVC pipe (#5) and delivers it to a 35 gallon plastic barrel which is the surge tank (#1). When the surge tank is full, the 2" diameter PVC siphon pipe (#2) is also completely filled with water and automatically begins to siphon at a rate faster than the pump is filling the tank. When the surge tank is empty, the siphon sucks in air and stops. The pump continues delivering water into the surge tank and the cycle repeats itself.
    [​IMG]
    Waikiki Aquarium Coral Tank Surge Device Much larger or much smaller devices can be constructed on the same basic plan although the pump and pipe sizes have to be scaled up or down as the dimensions change, particularly the vertical dimensions. At this time all I can suggest is trial and error for sizing, although some details for larger systems are presented below.
    Trouble-shooting
    Sometimes when the surge tank is full the siphon never really gets going. Instead, water flows out the siphon pipe as fast as the pump is pumping water in. To remedy this, we have placed the discharge end of the siphon pipe so that it is underwater at all times (position #9). This creates a bit of back pressure in the pipe, allowing the water level in the upper surge tank to rise a bit higher and thus start the siphon. Also a smooth bend at the top of the siphon, rather than right-angle bends as shown in the diagram, will facilitate siphon start-up.
    At other times the siphon won't start no matter how high the water level is in the upper reservoir. We reasoned that this is due to air trapped in the discharge siphon which has no where to go because the lower end of the pipe is always under water. To overcome this problem, we installed a 1" PVC air-vent pipe (#3) at a point on the siphon just above the highest water level in the aquarium (at position #1O). But this air vent may also prevent the siphon from starting and therefore a mechanism is required to close it at the critical moment when the siphon is to start. To avoid using a valve, which increases maintenance, we simply ran the air vent pipe back up into the reservoir tank with the opening of the air vent set just at the upper water level in the tank (position #8). The rising water acts like a valve to close off the opening of the pipe thus allowing the siphon to begin-presto, no moving parts! Note: an air vent pipe smaller than 1" in diameter may work, but we find they clog too easily with salt and therefore require more maintenance.
    [​IMG]
    Two coral culture tanks with surge devices (Photo by: Dr. Bruce A. Carlson)
    Unfortunately, once the siphon starts the air vent quickly reopens and sucks in air like a venturi. The air discharged into the tank may be disturbing to aquarists who don't want bubbles in their aquariums. This can be resolved by installing a simple flap-valve or check-valve on the air vent, but there will always be some air and bubbles discharged into the aquarium.
    Sometimes the siphon won't stop. A 45' angle cut at the intake end of the siphon pipe, as shown on the diagram, can resolve this by allowing more air to be sucked in when the water reaches the bottom of the surge tank.
    Drawbacks
    Depending on the size of the surge tank, the fluctuation in water level in the aquarium can be several inches (3" in our set-up). We have not figured out a simple way to resolve this problem to monitor evaporation in a closed system. One possible solution would be to install a float switch in the aquarium or a separate reservoir and set it for the lowest "normal" water level. When the water level drops below that mark because of evaporation, the float switch will activate the inflow of new replacement water. Of course, this will be periodically interrupted when the surge device dumps water back into the aquarium but nonetheless it should work.
    Besides space requirements, the other annoying part of these surge devices is noise. The gurgling sound when the siphon starts and the sucking sound when it stops can be very disturbing-definitely not recommended for the bedroom if you want a good night's sleep!
    Applications
    We have a 200 gallon surge tank fitted with a 6" diameter PVC siphon constantly filled by a 1.5 hp pump that delivers a powerful surge of water to our outdoor 7,000 gallon "Edge of the Reef" exhibit. This device has been in continuous operation since 1986 and has required virtually no maintenance except for pump repairs.
    [​IMG]
    Coral tank at Waikiki Aquarium (Photo by: Dr. Bruce A. Carlson) All of our outdoor culture tanks are fitted with 33 gallon surge tanks (as in the diagram), while our indoor 390 gallon exhibit tank is operated by a 0.5 hp pump which lifts water over 6' to a 55 gallon surge tank that delivers a powerful jet of water every three minutes via a 3" PVC siphon pipe.
    Wilfred Fong of the San Francisco Aquarium Society recently built one of these devices for his home aquarium after visiting the Waikiki Aquarium. His surge tank is much smaller (about 10 gallons) but it still produces a good surge of water to his reef aquarium.
    Our newest exhibit will have two surge tanks, both operated from a single pump and each delivering surge to different points in the aquarium. One surge tank will be 55 gallons and the other 35 gallons so that the periodicity of the output of the two tanks will vary. Occasionally they will both discharge simultaneously creating significant churning of water in the exhibit. To handle the combined output of the two tanks we will add a 150 gallon sump at the same level as the exhibit aquarium connected by a 19" long x 2" high overflow slot to allow the excess water to flow from the exhibit tank to adjacent sump where it will be pumped up to the surge tanks (similar to the diagram in Delbeek and Sprung, pg. 170).
    Once you build one of these tanks and learn its idiosyncrasies you will find it a very useful device for a variety of situations requiring a strong but periodic surge of water. Best of all, once you get it started, it will run forever.
    Reference:
    Delbeek, J.C. and J. Sprung, 1994. The Reef Aquarium. Ricordia Publishing, Coconut Grove, Florida.


    Typical Diagram:

    [​IMG]
     
  5. seank

    seank Thread Starter

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    Marine Aquarium Circulation System

    Depending upon what you are trying to propagate in your system, water current can be of varying significance. For fish-only tanks, intra-tank currents may be of little consequence. If your tank is simulating a tide pool or lagoon, very low or sporadic currents might be suitable. As you desire to propagate creatures that normally live in tidal zones or reef flats bounded by a barrier reef, you will want to seriously consider additional means of current generation beyond that constant cross-flow created by your circulation pump. Of course if you are into the small-polyped stony (SPS) corals that frequent the barrier reefs of coral atolls, you will have to go to extraordinary measures to move a large volume of water in a random fashion to simulate the surging currents found on the reef.
    Why do some sessile creatures need current? Often they require flowing water to not only bring them their food source, but more importantly to wash away the concentrated waste products exuded from their bodies as a result of their normal metabolic processes. Some creatures will literally drown in their own waste products if they are not washed way by some outside influence (ocean currents).
    Certain species, especially Xenia, are thought to facilitate the waste elimination process by rhythmically pulsing the extremities of the polyp. Even so, pulsating Xenia still prefer significant current in order to thrive. Other species of soft corals expand and contract their entire bodies on a diurnal cycle which this author believes to be an aid in shedding waste products from their outer layers while also dislodging entangled detritus, silt accumulations, and perhaps ectophoretic creatures which have sought refuge amid feeding tentacles during the day. The Sarcophyton (leather) coral is an example of a sessile creature that can modify its texture to become very smooth and contracted to allow currents to cleanse its surface.
    Ocean currents originate from several sources. Lunar- and Solar-induced tides are generators of sustained constant (but regularly alternating) currents. Wind-driven tides, known as “seiches”, create a similar effect. Estuarine currents are caused by runoff of fresh water rivers as they enter the coastal oceans over the planetÕs continental shelves.
    Lesser known sources of current generation to most aquarists are the various density currents resulting from temperature and salinity gradients in the ocean. As polar ice forms from sea water, 70 percent of the sea salt is expelled. As the ice thaws and refreezes, it becomes more pure, eliminating 70 percent of its remaining salt content on each refreezing cycle. The eliminated salt goes into the unfrozen sea water making it more dense, so it sinks. The sinking higher density (saltier) sea water creates a current as it sinks and flows along the bottom away from the polar regions toward the equator. Most of this current activity occurs at great depths over the abyssal plains and does not affect the kind of creatures that we normally keep in our aquaria, but salinity gradients do exist closer to land.
    For example, the Potomac River which flows from the Washington D.C. area out into the Chesapeake Bay and ultimately the Atlantic Ocean, has a salt water wedge that is a density gradient countercurrent which flows up stream along the bottom of the fresh water Potomac River. This salt wedge extends all the way up into the tidal basin around which the cherry blossoms of our nation’s Capitol bloom.
    Similarly, density gradients can be caused by temperature differences in ocean layers. These can be local, such as the night time cold currents which come in after dark to bathe the coelenterates along Florida’s John Pennekamp Coral Reef. Globally, some of the strongest currents in the world result from density differences aided by the wind (e.g., the Gulf Stream and the Kuroshio current).
    The Sun is the energy source for most of the world’s currents (except for gravitational tides or anomalous phenomena like tsunamis). The Earth is a great heat engine driven by the Sun’s radiated energy. This creates violent storms in the Earth’s atmosphere which in turn impart energy into the ocean. Most wave action is wind-driven. Storms in Antarctica create waves that propagate all the way to the tropics. Wind-driven waves are the major source of surge over the tropical reef systems of the world. Wind-driven wave surge causes a circular motion of water molecules in the vertical plane. When this wave action encounters an obstruction such as a reef, a back and forth surging of the water is manifested over the reef. As the water column (surface-to-bottom) becomes too shallow to support waves of a particular wavelength, the wave will rise up and “break” across the obstruction in the familiar fashion sought by surfers. This is true for large, long period waves. [​IMG] The tiny waves on the surface of the ocean (“chop”) are generated locally by wind, and these too cause currents when passing over objects very close to the surface. The region in which surface wave action is instrumental in surge formation is called the mixing zone and extends no deeper than most photosynthetic corals live. Steady currents found at greater depths usually have their origins somewhere other than the local mixing zone.
    Therefore, when designing a current generator for aquaria, one must consider in which region of the ocean the coral thrives, and what type of wave action is found there. Typically all of the coral animals found in tropical aquaria will come from the mixing zones of the worldÕs oceans and usually in the upper 10 meters. Wave makers for invertebrates coming from 30 meters of water will need zero to constant currents, while those coming from 10 meter habitats will prefer surging currents, and those living within meters of the surface may require large, random, multidirectional blasts of current to simulate violent surge and breaking waves.
    Constant currents can be generated by a simple circulation pump, while surging currents are often implemented by cycling a pair of opposing circulation pumps to first pump water in from one side, and then the other. Oscillating power heads, depending on their placement, can also perform this function. Violent chaotic currents are frequently created with “dump buckets” which slowly fill up and then discharge their contents into the aquarium rapidly by dumping or by valving through large diameter pipes.
    Alternating pumps are expensive because two pumps are used to move a volume of water equivalent to what a single pump would move (since both pumps never operate simultaneously). A timing controller is also required to cycle the pumps. Oscillating power heads (or any power heads, for that matter) are ugly additions sticking down into your aquatic garden. Dump buckets are very effective, but require lots of space (usually above the aquarium) and may require additional pumps and valving. Worst of all, they are noticeably noisy!
    My aquarium was designed to coexist with people, being placed in a wall between the family room and breakfast room. Though there was room for a modest dump bucket system, the noise and potential for splashing and salt creep made such a current generator ill advised. When designing the system I chose to replicate current conditions found deeper on the reef at a depth of about five meters.
    At five meters one would expect some energetic surging action, but mostly a slow, relatively constant back and forth current with some static flow areas. This environment was achieved using one Little Giant 4MDQ-SC pump (about 640 GPH with a 12-foot head) and a Mag Drive 7 (about 700 GPH with no head). I designed a special valve that allows the single Little Giant 4MDQ-SC to supply a bidirectional sinusoidal flow alternately emanating from one end of the show tank to the other.




    [​IMG]

    The special valve is driven by a small gearmotor taken from a surplus variac (motor-driven variable autotransformer) used in Atlanta’s low power TV Channel 57 transmitter. This motor was free, but almost any synchronous 60 Hz AC clock motor would have worked. The motor turns a geared output shaft at 1 RPM. This in turn drives a valve made from PVC pipe and a machined section of Delrin bar stock with orthogonal holes. As the Delrin cylinder rotates within the PVC structure, water from the single pump is allowed to flow from the single input port to one of the two output ports (the seal is merely an “interference fit” between the Delrin shaft at 0.500" diameter and the Teflon hole at 0.500". The bushing length is about 3 inches, so it doesn’t leak, but the Delrin-Teflon interface is self-lubricating, so it is still easy to turn.)





    [​IMG]




    This results in full flow out each of the output ports once every 15 seconds. The flow intensity from each of the valve output ports is sinusoidal and phased by 90¡ relative to the 1 RPM rotational period.





    [​IMG]



    Each output port is connected to one of the inflow pipes located at the ends of the show tank. When port one is open (and port two is closed), water flows from right to left across the show tank reef. When port two is open (and port one is correspondingly closed), water flows from left to right across the show tank reef. During intermediate states, both valve ports are supplying a portion of the maximum current flow that varies by the sine or the Delrin cylinder angle for port one or the cosine of the angle for port two. The valve is designed to deliver a flow corresponding to the relation below:
    [​IMG] This means that the show tank receives the maximum possible flow at all timesÐ only the flow vector is changing.
    This system provides a realistic wave action at less cost than alternately-switched twin pumps. A twin pump arrangement provides a binary flow which starts up abruptly and cuts off abruptly. Besides being harder on the pumps than continuous operation, the wave action produced is unnatural. Recall that natural wave action produces a rolling motion in the vertical plane. When a wave encounters the reef, it is transformed into a sinusoidal back and forth surge just like that produced with my valve design and a single pump. Twin pumps produced sudden blasts of full-force current that terminate just as abruptly.





    [​IMG]

    Does this matter to the coral? Who knows... but the single continuously-operating pump/valve system is more economical and doesnÕt present the potential for electronic interference with radio and TV reception that exists when inductive devices such as induction motors (used universally to drive all brands of large aquarium circulation pumps) are repeatedly switched on and off.
    Now let us consider the method used to cause short term high velocity turbulence which might be encountered at a depth of 5 meters as a result of nearby breaking wave action. Dump bucket noise was unacceptable and the use of power heads was aesthetically displeasing. My solution was to mount a circulation pump outside the aquarium with a clear suction pipe placed in one corner and a clear acrylic flow-delivery pipe leading to the geometric center of the top of the aquarium.




    [​IMG]


    Central Distribution System (top view)

    An acrylic distribution head connects to the flow delivery pipe through a freely rotating interface. The rotating interface is constructed from a PVC separable pipe union. The pipe union is threaded on both ends and has its stationary half fixed to, and penetrating through the 0.5 inch acrylic top of the show tank. The acrylic flow delivery pipe screws into the pipe union to form a watertight (but removable) joint.




    [​IMG]




    Central Distribution System (view from water surface inside show tank) The acrylic distribution head threads into the freely rotating lower half of the pipe union on the lower surface of the show tank top. Three exit ports direct water out of the distribution head. Two are angled down and away from the center of rotation to form an intense sweeping current across the reef surface as the distribution head rotates. The third exit port provides a tangential jet of water that drives the rotation of the distribution head at an approximate rate of 12 RPM while stirring the surface waters and causing turbulence on the upper sections of my reef.




    [​IMG]

    Acrylic Distribution Head

    The acrylic distribution head is invisible above the water’s surface and only the three clear acrylic exit ports extend below the surface, and then only about one inch. The entire arrangement casts no noticeable shadow and provides periodic random high intensity currents in a most unobtrusive manner.
    Presently this central flow system is energized under computer control for a few minutes each hour, with longer “on” times during the mid day hours than during the night. The reasoning is that the ocean wave action is more energetic during the day time when the Sun creates thermals and gyres that churn the sea surface more actively than at night. Many of my corals are also retracted at night, so the periodic waste-removing cleansing action produced by this semi random current would have little effect after dark.
    Aside from the very standard pumps employed, all of the current distribution systems described were homemade using surplus materials, pipe stock and fittings available from local building supply houses, and a measure of common sense.
    Addition of Surge Devices

    The rotating central circulation system worked well, stirring the water between the reef escarpments, but due to the rather high minimum rotational frequency of the central nozzles (approximately 0.5 Hz at its slowest), the current pulses striking the surface of the reef were unlike those occurring in nature. A longer period between current pulses seemed more desirable. In an attempt to simulate this, the pump driving the rotating central circulation system was timed to go on and off for periods of varying duration once per hour. This proved to be too stressful for the Supreme Mag-Drive 700 gph pump’s impeller. It failed after three months of intermittent use. A post mortem on the pump revealed that stress fractures occurred in the impeller blades due to the sudden shock each time the pump was energized. Once one blade broke away from the impeller shaft, it would interfere with the remaining blades and cause them to shear off as well. Based on the possibility that the original impeller was defective, a second impeller was installed under the pump warranty. Over a similar period of about three months of intermittent use, it too failed in the same manner.
    Clearly the design of the Supreme Mag-Drive pump was not suitable for intermittent duty and something else had to be tried. It was at this juncture that I decided to try Carlson surge devices. These would have to be custom made to fit above the show tank in the limited space available on either side of the light hood.
    A Carlson surge device provides an intermittent flow of moderate duration (a function of the surge device reservoir volume) and adjustable surge frequency (a function of the reservoir fill rate). The surge produced is fairly realistic in that it creates a constant mass flow during the surge, and can be timed to provide surges of duration similar to those encountered on the wild reef.

    In my 325 gallon reef system, two three gallon surge devices are used. To save money, a single 500 GPH 2MD-SC Little Giant pump runs both devices. One surge device is dedicated to each end of the show tank. Water volume pumped into each of the two reservoirs is adjusted by independent valves. The siphon tubes are 1-inch schedule 40 PVC pipe which is split just above the water’s surface and distributed through equal 3/4-inch pipes to either side of each end of the show tank. Loc Line segments terminating in a 3-inch fan diffuser allow the output to be directed on the sides of the reef at either end. Only the edges of the black Loc Line fan diffusers penetrate the surface of the show tank, the rest of the distribution tubing just above the water surface is invisible to those viewing the show tank. The input to the pump is a clear acrylic tube of 1-inch diameter that extends to a depth of about nine inches in one corner of the show tank. A clear plastic grate prevents the inhabitants from being sucked into the continuously-running pump. To prevent any pump noise, it is mounted on a concrete wall adjacent to the aquarium command center in the basement.
    The reservoirs are rectangular boxes having all joints and ports secured with Weld*on-40 (“liquid Plexiglas”). Because the reservoirs are tall (approximately 24 inches), internal cross buttresses of acrylic have been included during the construction to keep the reservoirs from fatiguing after repetitive filling cycles. To further assure that the thin wall (0.125-inch) acrylic does not flex, aluminum angles were cemented to the outside corners using the flexible silicon adhesive marketed in the U.S.A. under the name “Goop”.






    [​IMG]
     
  6. seank

    seank Thread Starter

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    Continue from post 04

    The surge devices are adjusted to trigger every 30 to 45 seconds with a surge lasting approximately 30 seconds. They trigger asynchronously and provide a realistic periodic surge over the upper and inner sides of the reef escarpments. This has greatly improved show tank circulation and augments the more general sinusoidal back and forth surge from the primary circulation pump and its alternating flow valve. That circulation is improved is without question, as green star polyps which used to languish, now spread along the rocks in the direction of the flow.
    There are some things to be considered when using the surge devices. First, my system was sized with adequate sump volume to accommodate back-flow from the upstairs distribution pipes in the event of a power failure. With the inclusion of the two 3-gallon surge devices, as much as six gallons can be suspended above the show tank at any time. During a power outage, these reservoirs drain back through the surge device pump into the show tank. The show tank can not accommodate the extra six gallons, so it goes over the overflow and down into the sump. Since the sump was originally sized to accept only the back flow from the distribution system pipes, the addition of six extra gallons of water is too much and the sumps overflow.
    In anticipation of this an overflow pipe has been added to allow the extra water in the sumps to be diverted into a reclamation drum. When the power is restored, the entire system functions correctly, but the sumps are six gallons lower in level than they should be. A float switch in the reclamation drum then activates a pump that returns the six gallons back to the system. Were this to fail, the automatic refill system would gradually replace the six gallons of salt water with six gallons of deionized fresh water, reducing the overall specific gravity of the system by 3 percent. In a new system, this could be avoided by using deeper sumps.
    Another consideration is that as the reservoirs fill, the amount of water leaving the show tank is diminished. As a result, the level of the sumps will drop. When the surge devices trigger, more water will be delivered to the sumps causing the level to rise. In the worst case, both reservoirs fill simultaneously and trigger simultaneously. This causes about a 0.25-inch change in the show tank water level and about a 1-inch change in the sump level. Since this occurs over a period of about one minute, the automatic water replenishment system is not activated because the sensory time constant for that device is much slower. Were one surge device reservoir to fill while the other triggered, there would be no net change in water levels. Since the operation of the two surge devices is asynchronous, changes in show tank and sump levels are rarely noticeable.
    A final note is that at the beginning of a surge cycle, and again as the siphon “breaks” at the end of a surge cycle, tiny bubbles are entrained in the surge flow. These typically last for only a moment, but some find them objectionable. In reality real wave surges often do entrain air in the form of tiny bubbles that are driven beneath the surface when a wave encounters a shallow reef.




    [​IMG]






    Return to Michelson Aquarium.



    This is the link I got the info from:


    http://avdil.gtri.gatech.edu/RCM/RCM/Aquarium/CirculationSystem.html


     
  7. seank

    seank Thread Starter

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    http://www.guarriello.net/aquarium.htm

    Check this guy out, small tank, but all the bells and whistles. I like his surge device as well as his DIY Small tank overflow.. Click on the link he provided to see the diagram
     
  8. seank

    seank Thread Starter

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  9. seank

    seank Thread Starter

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  10. sunburst

    sunburst

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    Holy Schmokes Sean, thats a lot to absorb in one night. Was only able to play the last clip. I did briefly investigate this option but was swayed away by public opinion at the time and that was that they were bulky and cumbersome. But from the clip shown they certainly seem very effective.
     
  11. seank

    seank Thread Starter

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    Yip, alot to absorb, but good reading though. I am seriously cosidering one of the above options, as I would like to get rid of all the pumps in the display area. I originally planned the tank to not have any pumps in the display area. So hopefully I'll get the waterflow right and the Cyano gone
     
  12. Warr7207

    Warr7207

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    That tank makes me seasick :puke: ;)
     
  13. Punk

    Punk

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    awesome sean! i'm also busy trying to build 2 surges so this thread is great! :thumbup:

    the common one's besides the normal carlson that i know of (perhaps we could expand on each with pro's & cons):
    - reverse carlson
    - borneman
    - dump bucket? :whistling:
     
  14. Mekaeel

    Mekaeel Moderator MASA Contributor

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    thats is awsome!havent read through the threads,just watched the videos and im very impressed.gotta make myself one of those
     
  15. HenkHugo

    HenkHugo

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    guys watch out for posting full articles.... some guys gets twitchy about it
     
  16. lindsay pollard

    lindsay pollard pipefish

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    this is an amazing thread sean gives me something to think about ,very cool dude
     
  17. jacquesb

    jacquesb Retired Moderator

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    Thanks for listing the different options available for creating surges, Sean. Thanks too for sharing the information found.

    I just think that we should perhaps get some clarity on the posting of information from other sources, as it seems that there have been multiple warnings...

    Don't worry about this now. I have launched a discussion with the MASA admins/mods....

    Brilliant info - though.
     
  18. Mekaeel

    Mekaeel Moderator MASA Contributor

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    glad to hear this is been sorted out
     
  19. jacquesb

    jacquesb Retired Moderator

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    OK everyone. I think that Copyright infringement is not at all applicable here. The Internet is a VERY difficult place to fight copyright infringements, as each country has it's own law on this. And, it would not be worthwhile to anyone to try and spend money and time on fighting a law over international boundaries.
    Especially taking into account that someone who wants to fight copyright infringement, HAS to proof that the copyright was actually "infringed". And this is not so easy to do, in a court of law. Most copyright court cases are chucked due to a shortage of real proof.

    That said - I have asked and received the answer that AS LONG AS THE LINK / URL to the original location is posted as well - which seems to count as "internationally accepted courtesy", then all SHOULD be ok.....

    So - Sean - post on man.
     
  20. Mekaeel

    Mekaeel Moderator MASA Contributor

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    thanks Jacques,could you please clarify it on my Zoanthids thread aswell
     
  21. seank

    seank Thread Starter

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    Thanks Jacques, knew about this, hence the reason for me posting links with all the posts I've done..
     
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