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Current versus Flow

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  • Current versus Flow


    I'm trying to understand how to think about current versus flow, and when you emphasize one versus the other. In my present circumstance, I seek feedback on whether I've engineered too much current and should instead emphasize flow, and how a (my) chosen flow pattern fits into that.

    90gal tank.

    My Filters:
    (1) Eheim 1262 (898gph) with a needle wheel that distributes co2 . Output of the 1262 is split to rear L+R of tank, then, a loc-line Y connector is at each output for each side of this split. Loc-line at each Y connector is flat flare with hole nozzle (see link).
    (2) Three Eheim 2028 canisters (277gph), each with separate input and output. One output = spray bar, other two outputs connected to loc-line standard flares (see link).
    (3) MP20 VorTech pump (probably driven at 80percent max).

    Total gph:
    In total excluding the VorTech cause I don't know how to estimate it: 898 + 277x3 = 1729gph. Of course lower with needle wheel, filled canisters, head, etc. But still that seems alotta current.

    All loc-line is 1/2". I describe the loc-line output nozzles so you can get a sense of current that would come out. In total there is 1 spraybar (Eheim 2028), 2 regular loc-line flares (from two remaining 2028s), 4 flat flare nozzles with holes delivering co2 from Eheim 1262 (two from each Y at L+R back of tank), plus VorTech.

    Flow pattern:
    Spraybar location = right narrow side of tank at top, pushing water across top from right to left; VorTech located left narrow side of tank 6 inches down, pushing water from left to right; all other loc-line flares are split to L rear and R rear, mostly directed about 1/3 down toward front 1/3 of glass, with two of the four co2 flares directed toward rear wall.

    I've read so much here about the importance of good co2 distribution via current. But now I'm thinking maybe I went way overboard and maybe I should forget about current and focus on flow. Plants and fish seem "OK" but the viable swimming area does seem restricted and some planting locations do have too much current.

    Q1: is this overall too much current?
    Q2: is the flow pattern I have chosen sensible?
    Q3: should I skip worrying about current and increase flow? One way I could do that is to switch to all 3/4" loc-line, and NOT use the flat square nozzle with holes for co2 out, or switch to ALL regular round nozzles. I chose flat flares at set-up because the open round nozzles seemed too weak and I wanted good current to move co2.
    Q4: loc-line nozzle types & preferences? standard flares vs. round open nozzles? (why choose one versus the other?)

    Thanks for any input. Sorry for all the gory detail but I figured some might be relevant.

    Flat flare nozzles with hoses used for co2 output from Eheim 1262 ; the small holes increase pressure & current out

    Regular flare nozzles used for two Eheim 2028s
    Last edited by growitnow; 03-06-2012, 03:03 PM.

  • #2
    Well, you can start high and reduce the flow down and see.

    Every tank will be different, same for CO2........

    Depends on the planted tank's structure and physical barriers, point sources of flow.


    • #3
      In my opinion, you want both just don't go overboard. I also agree with Tom that how much is dependent on your particular situation.

      The idea is to deal with two things- ensure you have enough movement to get detritus to the filter and get nutrients into the plants.

      In the aquarium and even around the leaves themselves, there is a boundary zone that forms. The water movement needs to be enough to disrupt these zones.

      I use the filter outflow to provide current and periodic high flow from an MP10 Vortech.

      Good luck




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