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Thread: New scrubber build

  1. #1

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    New scrubber build

    Hey guys need some info....

    75 gallon
    2 pinches of flake daily
    1/4 frozen cube daily

    What size of screen do I need and one or two sided screen.
    Do I need lights on both sides or just one?
    What wattage light do I need....and is the wattage divided, if I have two sided lighting?
    Example.... if I need a 100 watt...do I do 50 watts on 1 side, and 50 watts on the other?
    If I do a bigger screen than usual......thinking about doing a 10x10.
    Equally square or wider then longer?

    Thanks

  2. #2
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    I usually recommend doing a 2 cube/day screen as a minimum. if it's oversized, it won't be more than double what you need, and you will likely 'grow into' it. 6x4, 5x5, 4x5, etc. Find something that fits your space.

    Always do double sided if you can.

    for lighting, if you're going with CFL, for a 24 sq in screen, you would need a total or 24W for regular light levels (18 on / 6 off) or for the "high intensity" you would go to 24W per side.

    For 100 sq in, which is 8 cubes/day capacity and is likely way too big for your tank, you would need 50W per side or 100W per side for high intensity. I wouldn't quite go there yet. The only reason to do this on your tank is if it is a hot mess, neglected, nutrients out of control for a long time, algae on all the rocks, etc.

    Width should be driven be available flow. 35 GPH per inch of screen width is recommended. You can go lower but you lose filtration capacity and can't run lighting as long without burning. If you have more flow available, you can increase the lighting intensity as long as you ave enough nutrients for that algae to grow (i.e. you have room to grow)

  3. #3

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    Well I definitely have a mess......would it be bad to do a 10x10 with 50 watts on each side. What would be a draw back on this?
    To much overkill? Going to have MaxiJet 1200 with a gravity fed drain to my sump. Probably going to have to tone down the flow a bit, with a little tweeking should be good I think? Just as long I get a good flow going equally down the screen...right.
    Just drawing and planning it now...not started building yet, need to be sure first. Tank has been going on for 5 years....and still fighting HA. Tired of dealing with it!!!

  4. #4
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    An MJ1200 - is that just for the screen? That's not enough for much of anything as MJs have really bad head loss. Maybe good for a 4" wide screen that starts 12" above the waterline. If that's your return pump for the tank, then it's not good for anything, and might be part of your overall problem.

    The 35 GPH/in will give you the even flow down the screen. I would not oversize it to 10x10, that's just a bit too much IMO. 8x8 would be your max I think

  5. #5

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    MJ1200 would be for the screen. The drain would be gravity fed to my sump. 4" wide screen above water line....what waterline? My design is a 18 gallon plastic tub next to my DT, then drained into my sump. So by using a MJ1200 my screen would be max 6x6.....36sq in x 35ghp= 1260...right? 12" above the plastic tub waterline, or the sumps? Eventually going to put it in my overflow drain to my sump....just trying this first so I don't have to mess with my plumbing on my DT.

  6. #6
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    Welcome.

    Scrubbers are sized according to feeding. Nutrients "in" (feeding) must equal nutrients "out" (scrubber growth), no matter how many gallons or liters you have. So...

    An example VERTICAL upflow or waterfall screen size is 3 X 4 inches = 12 square inches of screen (7.5 X 10 cm = 75 sq cm) with a total of 12 real watts (not equivalent) of fluorescent light for 18 hours a day. If all 12 watts are on one side, it is a 1-sided screen. If 6 watts are on each side, it is a 2-sided screen, but the total is still 12 watts for 18 hours a day. This screen size and wattage should be able to handle the following amounts of daily feeding:

    1 frozen cube per day (2-sided screen), or
    1/2 frozen cube per day (1-sided screen), or
    10 pinches of flake food per day (2-sided screen), or
    5 pinches of flake food per day (1-sided screen), or
    10 square inches (60 sq cm) of nori per day (2-sided screen), or
    5 square inches (30 sq cm) of nori per day (1-sided screen), or
    0.1 dry ounce (2.8 grams) of pellet food per day (2-sided screen), or
    0.05 dry ounce (1.4 grams) of pellet food per day (1-sided screen)

    High-wattage technique: Double the wattage, and cut the hours in half (to 9 per day). This will get brown screens to grow green much faster. Thus the example above would be 12 watts on each side, for a total of 24 watts, but for only 9 hours per day. If growth starts to turn YELLOW, then increase the flow, or add iron, or reduce the number of hours. And since the bulbs are operating for 9 hours instead of 18, they will last 6 months instead of 3 months.

    HORIZONTAL screens: Multiply the screen size by 4, and the wattage by 1 1/2. Flow is 24 hours, and is at least 35 gph per inch of width of screen [60 lph per cm], EVEN IF one sided or horizontal.

    FLOATING SURFACE SCRUBBERS WITH RIBBONS: Screen size is the size of the box (Lenth X Width), and is 2-sided because the ribbons grow in 3D.

    LEDs: Use half the wattage as above. 660nm (red) is best. You can mix in a little 450nm (blue) if you want.

    Very rough screen made of roughed-up-like-a-cactus plastic canvas, unless floating surface, which would use gravel and strings instead.

    Clean algae:

    Every 7 to 21 days, or
    When it's black, or
    When it fills up, or
    When algae lets go, or
    When nutrients start to rise

  7. #7
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    Quote Originally Posted by WillieD View Post
    MJ1200 would be for the screen. The drain would be gravity fed to my sump. 4" wide screen above water line....what waterline? My design is a 18 gallon plastic tub next to my DT, then drained into my sump. So by using a MJ1200 my screen would be max 6x6.....36sq in x 35ghp= 1260...right? 12" above the plastic tub waterline, or the sumps? Eventually going to put it in my overflow drain to my sump....just trying this first so I don't have to mess with my plumbing on my DT.
    reagarding the MJ. They just don't have the head pressure available. I tested this pump against an Eheim Compact 1000 and a Rio 1100. The distance above waterline is the distance from the operating water level of the sump to the centerline of the slot pipe. This is your vertical head. The slot pipe generally adds another 2 or 3 feet of head, depending on the pump (some are stronger). So when I 'benchmark' tested these three pumps on a bare screen (no algae) I think the actual measure flow rates across a 6" wide screen were 195 for the MJ1200, 205 for the Eheim, and 230ish for the Rio.

    I had shipped about 20 or so of the Eheim pumps out along with some of my first batches of L2 scrubbers. Then I tested the actual output on one of mine with a full screen of algae and it was about 70 GPH. I switched to the Rio as it has much better reaction to head pressure.

    If you go with a 6" wide screen you want 6x35 = 210 GPH actual flow (this is pump max minus head loss, if you go by a chart, but it is best to actually measure it)

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