Water movement

Discussion in 'Filters, Filtration and Pumps' started by Henrik, 18 Nov 2008.

  1. Henrik

    Henrik Member

    Messages:
    67
    Location:
    Chester, Cheshire
    Hi there,

    my first post - thanks to Jim at The Green Machine for pointing out this site to me!

    I recently cleaned up my 325l tank and planted it up with some great plants from TGM. I now have a question about filtration, or more precisely water movement. I am using a Back to Nature modeled background which has probably some 25l of space behind it. I divided this space into three chambers, using thick foam pads, of which the middle one is filled with filter foam cubes. I am pulling in the water through a hole on the left hand side with an Eheim 2322 thermo filter (500l/h), through which it is filtered mechanically, before pumping it into the second chamber of the background, which contains the foam cubes. The water runs through the main foam cube filter before being soaked up again by another E2322 (I use some more biological filter material in this filter) in the chamber on the right hand side, before being pumped out through a hole at the top of the background. There is another outlet at the bottom of the background for possible excess water to flow through.

    I am very confident that the filtration is working - to my understanding the slower the pass through rate, the better the filter will work. I am getting concerened though about water movement, after reading a few posts on the forum. I do think it moves reasonably much, but I read about desired flow rates up to 10x the tank content, in order to effectively spread CO2 and nutrients...

    What do you think, thanks in advance for your help.

    Henrik
     
  2. Steve Smith

    Steve Smith Member

    Messages:
    4,428
    Location:
    Leamington Spa, UK.
    Sounds like an intriguing setup :) How about some pics?

    Do you inject CO2 at the moment? you could add a power head inside the tank to increase the water flow around the tank. Depends on your setup, and the direction of the flow etc :)
     
  3. Henrik

    Henrik Member

    Messages:
    67
    Location:
    Chester, Cheshire
    It is set up a bit like this (sorry, in German):

    http://www.back-to-nature.de/animation.htm

    except that I am using external filters and not pumps. I will try and get some photos done, although it might be difficult to get a good shot given it is all quite tight against the wall.

    Thanks for other views on the necessary flow rate in my planted aquarium!

    Henrik
     
  4. Steve Smith

    Steve Smith Member

    Messages:
    4,428
    Location:
    Leamington Spa, UK.
    It's almost like a sump I guess. Similar princaples? I could see it getting colonised by cherry shrimp really easily :lol: Don't worry too much if photos are hard to get.
     
  5. ceg4048

    ceg4048 Expert/Global Moderator Staff Member

    Messages:
    8,952
    Location:
    Chicago, USA
    Hi,
    This effectively looks like a mini-sump. What I don't get is why go through all this complication when you already have two filters (which will be easier to clean) that can do just as good a job at filtration by just adding some sintered glass media and a little bit of foam? Big tanks already have a problem with flow so really there is no advantage of slowing the flow just so that your mini sump can be more effective at biofiltration.

    The flow and distribution might seem OK now but as the plants increase in mass, and depending on light intensity you may find the flow inadequate. On the other hand, if the lighting is kept low to moderate and if you have an effective flow pattern and CO2 diffuser arrangement it might be fine. It's difficult top predict but the plants will let you know soon enough. You can always add powerheads to improve movement though, so you do have options.

    Cheers,
     

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