Fluidised sand bed filter

Discussion in 'Filters, Filtration and Pumps' started by Spider Pig, 11 Dec 2008.

  1. Spider Pig

    Spider Pig Member

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    Has anyone used one of these in a planted tank?

    Just wondering as thinking about my next tank and what sort of filtration I want for it. Read the basics about these in a book and thought that they might be useful in a planted tank (or any tank for that matter) given that they seem to be much more efficient biological filters.

    The main question is about flow rates through these- does it have to be low to stop the sand getting blown into the tank, and so you'd need extra pumps for flow in a planted tank.

    Any thoughts?

    Edit: just realised that there is a separate filter section- any chance a mod can move this thread please.
     
  2. LondonDragon

    LondonDragon Administrator Staff Member

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    I have seen Oliver Knott using these filters on his larger planted tanks. Don't know much about them though!
     
  3. Spider Pig

    Spider Pig Member

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    Some of the american websites tout them as great for planted tanks because they are a closed set up and so don't lose co2. The other advantage is that they seem to be able to react to changes in ammonia a lot quicker than conventional filters. I imagine this would be a big advantage in planted tanks as it would minimise ammonia spikes. The main problem that I can see with them is that they seem to need a low flow rate to prevent the sand getting blasted out. They do seem the way ahead for big heavily stocked tanks though.
     
  4. Spider Pig

    Spider Pig Member

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    Found this page about rainbow filter specifications:
    http://www.pentairaquatics.com/produ...duct.php?id=7#

    Interestingly it says that 9lb of media gives 642 square feet. Looking at my ehfisubstrat pro it says it has 450 square meters per litre which equates to 4843 sq ft per 1.8lb, or 24215 sq ft per 9lb.

    This means that ehfisubstrat pro has 37 times more surface area than sand- someone's telling porkies or underselling their product.
     
  5. Ed Seeley

    Ed Seeley Member

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    I have to say I think the performance claims for fluidised bed filtration such as these sand beds seem rather unbelievable. I have a fluidised filter in my pond, but it is plastic floating media kept fluidised by lots of air, which gases off ammonia and other things, introduces oxygen and stirs the media so it doesn't accumulate dirt and gives obvious benefits. I can't see why sand kept in suspension by a flow of water produces such amazing results. The only real advantage as far as I can see is that it keeps the media in suspension preventing dirt accumulating and removes excess biofilm from the sand.

    Personally I'll stick with sintered glass media.
     
  6. Spider Pig

    Spider Pig Member

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    From what I've seen this does seem to be useful if you don't have low flow but not high flow systems. I can see how it should have a greater surface area to sintered glass as it is effectively individual sand grains but like you say, it doesn't seem to have any great advantage in a planted tank.
     

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