Dual or single over flow

Discussion in 'Fish Tank Brands and Kits' started by ryan391, Dec 17, 2012.

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  1. smoyer

    smoyer Spanish Shawl Nudibranch

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    The boxes will be the same whether there is one or two. Is it a corner overflow?. Marineland uses a overflow but I believe you can either get a corner or and offsetting rear wall overflow with an aqueon tank.
     
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  3. HightechRedneck

    HightechRedneck Spanish Shawl Nudibranch

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    Think ahead. What type of stand pipe are you going to run? How quiet do you want it? are you ok with running a return over the back? As stated, flow really has nothing to do with it. you will want low flow through a fuge anyhow

    A durso style is simple but introduces air which is loud.

    I have a dual over flow 125. The large holes have 2 full suction straight stand pipes with good gate valves to control flow. 1 small hole is a return to tank that flows about 1000 gph. The other small is a dry emergency drain to the sump that is cut slightly above the overflow teeth's level. If I would get a 100% block in both drains the emergency drain will take the entire pump volume. This setup is DEAD quiet. The only thing you hear is a hum of the return pump. : )

    Think plumbing before you buy and what works best for you.
     
  4. m2434

    m2434 Giant Squid

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    There is no question that the organics are attracted to the air-water interface. Any amphiphilic molecule (which accounts for a good chunk of organics will be).


    The air-water interface, in reality, is a small area and molecules don't instantly end up there. The molecules float around, and there is a certain probability that they will end up in proximity and bind. If the air-water interface is saturated with molecules, there will be a lower probability of this. If they get skimmed over the overflow, they get mixed in the water. As long as this skimming/mixing, is occurring faster than the rate of binding, the amphiphilic molecules should be mixed in the water as a heterogeneous solution. So, this seems it should be determined by the rate of turnover, not the number of overflows. When the water comes in contact with the skimmer, the bubbles in the skimmer form a much larger air-water interface. So, to maximize the skimmer efficiency, the mixing needs to occur at a rate that maintains a air-water interface in the skimmer, that is saturated as much as possible. This should occur as long as the water remains a heterogeneous mixture. However, this seems that it should mostly depend on turnover. But as long as turnover is sufficient, it doesn't seem that there would be a gain in efficiency with increase turnover, or surface skimming.

    That is skimmer theory as I understand it anyways FWIW...
     
  5. ryan391

    ryan391 Astrea Snail

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    What is the volume of water drain/return difference between dual and single? I would think it would be double. I am not sure there is any benefit to that.

    What is the GPH per return on an Aquion vs Marinland overflow. I have a 75 marineland corner overflow now. Is it the same as a 120? Long story on why I am upgrading now but I was hoping to get into the bigger tank without a whole lot of investment. If I get a single corner overflow, I want to use my same return and sump as I have for my 75. I have an adjustable return pump that is not maxed out.
     
  6. m2434

    m2434 Giant Squid

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    I'm not 100% sure off the top of my head. I think the marineland is 700gph and aqueon are advertised at about 600gph each. So, I think they do claim it will double.
     
  7. smoyer

    smoyer Spanish Shawl Nudibranch

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    A 1in bulk head will let 800 gph flow thru. I think they are pretty equal
     
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  9. azjohnny

    azjohnny Bristle Worm

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    800gph through a 1" drain will sound like a toilet and order to make the drain quiet I would run 300 gph for each 1" drain
     
  10. Jlobes

    Jlobes Coral Banded Shrimp

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    Your skimmer theory seems accurate. But, that's for a protein skimmer. We are talking about surface skimming.

    And it's pretty simple, more surface area means more surface skimmed. That water which is now a mixed solution as you call it. Now flows down to the skimmer region... Which is where we come back to your theory on skimmers.
     
  11. m2434

    m2434 Giant Squid

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    Right, I agreed on the surface skimming, but surface skimming dozens,t remove anything until you get to the mechanical filtration. At that point, it tends to get mixed up again anyways. You could drop it into a filter sock, but the stuff bound to the surface may not be removed by a sock. Some may, some may not, but the stuff that is will probably tend to be whether or not it it concentrated. Something like a skimmer may benefit more from concentration . So, IIRC then, the point was the surface area versus the surface attraction rate. The surface area is relatively small and rate of attraction of amphiphillic molecules to the surface relatively slow when views in perspective of typical turnover rates. I.e. with a typical turnover rate, it seems to me that you are mixing faster than collecting. So, by the time it gets to the skimmer it seems it should be remixed anyways... Nothing wrong with more surface skimming though it may help something, just not clear to me what in practice. Having less space taken up by overflows should probably be more desirable to me, but completely a personal preference...
     
  12. Jlobes

    Jlobes Coral Banded Shrimp

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    I guess my point, is that regardless of the surface attraction rate, the surface is the only area we are removing water from a DT. So, in theory, if you double the amount of area you have effectively doubled your capacity to remove what particles are bound on the surface.

    Note that I have not mentioned flow rate in either of my posts.

    check this link:BeanAnimal's Bar and Grill - Silent and Fail-Safe Overflow System

    particularly this quote:

    Surface Renewal
    An extreme example: Take two identical 40' wide ponds that are fed with the same amount of water, one with a 4' wide dam and the other with a 40' wide dam. It follows that for the same flow (lets say 100 gallons per minute) over the dam, that the narrow dam will have a very thick waterfall and the wide dam a very thin sheet of water cascading over it. Now place an oil slick over both ponds! It will take significantly longer for the 4' wide dam to clear the slick fro the pond. Why? Because much of the water flowing over the dam is from below the surface! Now apply this logic to your tank, but instead of an oil slick, understand that the surface of the water attracts organics from the tank. The logical conclusion? For any given flow rate, the wider the overflow, the better your skimmer and/or in sump filtration will work!