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Thread: Screen size for tank

  1. #1

    Join Date
    Apr 2011
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    Screen size for tank

    Hi
    Could any one help me,what would be the screen size for a 610 litre tank,call me stupid but I am getting real wierd and large sizes when I try and work out the screen size and flow rate.Maybe I am just stupid.Also converting lt to gallons and cm to inches is not helping me.

    Any help would be great.
    Thanks

  2. #2

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    Re: Screen size for tank

    how will be your lightning?
    2 side?
    1 side?
    how the screen will stay?
    vertical?
    horizontal?
    just answer, and i convert for you ;D

  3. #3
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    Re: Screen size for tank

    Ok, the rule is that you start with the size of your tank (display only, and don't subtract rockwork, etc), in gallons. Then, you measure your flow rate either into your sump or out your jets (this means actually taking a container and timing how long it takes to fill it up, repeating several times, then extrapolating this out to GPH). Take your actual flow measurement result and divide by 35. This will give you screen with in inches. Take that number and divide into your tank size, and this will give you your screen height.

    For example, let's say you had a 90 gallon tank, and your pump push 300 GPH (measured). 300/35 = 8.5 inches. 90 / 8.5 = 10.5 inches. Thus the optimal screen size would be 8.5 inches wide by 10.5 inches tall.

    As far as the conversions go, because the screen size has a nice easy correlation between gallons of tank size and square inch dimensional area (L x W = tank) it is easiest to work in those units. That is probably your issue. I would convert your tank size from L to G and flow rate from LPH to GPH and work the calculations, then convert back to metric once you have figured out your necessary total square inches (L x W)

    Also note that this works for a screen lit from both sides. If you only light from one side, the L x W dimension must double.

  4. #4

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    Re: Screen size for tank

    Ok, so firstly,I will not be using my overflow/drain from my tank i will be using a pump.I would have my screen lights on both sides,I would like the screen to be vertical if possible but does not matter.What I would like to know is what screen size will work best,and what flow pump should I be looking at.It will be a closed unit,with the screen hanging out the bottom into my sump.Once I got the screen size,I can then get the rest of the equipment to build my scrubber.

    Thank you for your replies.

  5. #5

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    Re: Screen size for tank

    Quote Originally Posted by Floyd R Turbo
    Ok, the rule is that you start with the size of your tank (display only, and don't subtract rockwork, etc), in gallons. Then, you measure your flow rate either into your sump or out your jets (this means actually taking a container and timing how long it takes to fill it up, repeating several times, then extrapolating this out to GPH). Take your actual flow measurement result and divide by 35. This will give you screen with in inches. Take that number and divide into your tank size, and this will give you your screen height.

    For example, let's say you had a 90 gallon tank, and your pump push 300 GPH (measured). 300/35 = 8.5 inches. 90 / 8.5 = 10.5 inches. Thus the optimal screen size would be 8.5 inches wide by 10.5 inches tall.

    As far as the conversions go, because the screen size has a nice easy correlation between gallons of tank size and square inch dimensional area (L x W = tank) it is easiest to work in those units. That is probably your issue. I would convert your tank size from L to G and flow rate from LPH to GPH and work the calculations, then convert back to metric once you have figured out your necessary total square inches (L x W)

    Also note that this works for a screen lit from both sides. If you only light from one side, the L x W dimension must double.
    This is starting to make little more sense,thank you for explaining it.I wont be using my obverflow drain and this I think were I am getting it all wrong.What size pump will I need and how would I work it out.So once I have worked that out I can calculate a screen size.

  6. #6
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    Re: Screen size for tank

    Ok, so 610L = 160G, approx. Using a standard 24" wide fixture (for 24W T5HO lamps) you would want a screen that is 22" wide, so that's 160/22 = 7.2" tall. I would suggest that you DIY your lights and go with 3 lamps and reflectors on each side. The reflectors are usually 2.75 to 3" wide, so 3 wide would be about 8.25 to 9", I would try to find narrow reflectors in this case and make your "active" vertical screen area about 8.5 to 9" tall (add a little for the amount that gets inserted into the tube).

    So with a 22" long slot, you want 35 GPH, this works out to about 770 GPH, round that to 800 (because you're going to lose 15-20% flow in 6 months, before you clean your pump) and that works out to a 3000 LPH pump. So if you make sure to use the proper return hose size from the pump to the scrubber, your head loss will be minimal, and you could probably use a straight 3000 LPH pump, or a 3500 LPH pump with a valve to back it off if your flow is a little high, which you can open up a little each month to keep flow consistent between cleaning. Higher flow is just fine though so that might not be necessary.

    Also the acrylic enclosure will have to be well braced so that it doesn't warp from water contact and heat.

    Make sense?

  7. #7
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    Re: Screen size for tank

    0.5 actual (not equivalent) fluorescent watts per gallon MINIMUM [0.13 watts per liter].

    1.0 actual (not equivalent) fluorescent watts per gallon for HIGH filtering [0.26 watts per liter].

    1.0 square inches of screen per gallon, with bulbs on BOTH sides (10 x 10 = 100 square inches = 100 gal) [1.64 square cm per liter]

    2.0 square inches of screen per gallon, if vertical but lit on just ONE side. [3.28 square cm per liter]

    4.0 square inches of screen per gallon, if HORIZONTAL [6.56 square cm per liter].

    1.5 actual (not equivalent) fluorescent watts per gallon if HORIZONTAL [0.4 watts per liter].

    18 hours of lights ON, and 6 hours of lights OFF, each day.

    Flow is 24 hours, and is at least 35 gph per inch of width of screen, EVEN IF one sided [60 lph per cm].

    Very rough screen made of roughed-up-like-a-cactus plastic canvas.

    Clean algae off of screen every SEVEN (7) days NO MATTER WHAT YOU THINK.



    Feeding Guidline:

    Each cube of frozen food you feed per day needs 12 square inches of screen, with a light on both sides totaling 12 watts. Thus a nano that is fed one cube a day would need a screen 3 X 4 inches with a 6 watt bulb on each side. A larger tank that is fed 10 cubes a day would need a screen 10 X 12 inches with 60 watts of light on each side. If you feed flake, feeder fish, or anything else, you will need to blend it up super thick, strain out the excess water, pour it into a cube, and see how many cubes it is.

  8. #8

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    Apr 2011
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    Re: Screen size for tank

    Thanks guys ,it is all starting to come together,thank you for taking th time to explain it to me.So now I go and build my scrubber :lol:

    Thanks once again.

  9. #9

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    Re: Screen size for tank

    This is my scrubber exactly, except that I use the overflow drains instead of a separate pump. It's an SM100 design, but stretched to have three lamps rather than two on each side. I also have the drains coming into the tube on both sides to give more even flow across the screen. I DIYed the lamps since there aren't really commercial three lamp units available.

    I've got it on a 125 gallon. It seems to be working well, except I think it is overkill. My tank is fairly lightly stocked. If I had to do it again, I'd probably just go with a standard 2 lamps on each side. For your 160 gallon tank, if it is pretty well stocked, then it might be appropriate. However, it makes some sense to look at how much you are going to feed and size the scrubber to that. By SM's numbers, you can feed one 1 ml cube for each 10 square inches of (double sided) screen, so in my case, I could feed 16 cubes a day, which is a lot of food. I'm only at around half that and don't really feel the need to go more. If you are happy with 10 ml of food per day, then an SM100 style, with 2 bulbs per side would be fine.

    I used Workhorse 5 ballasts, some old reflectors, and Ice Cap waterproof T5 sockets. If I had to do it again, I wouldn't bother with the waterproof sockets. They added considerably to the expense.



    Quote Originally Posted by Floyd R Turbo
    Ok, so 610L = 160G, approx. Using a standard 24" wide fixture (for 24W T5HO lamps) you would want a screen that is 22" wide, so that's 160/22 = 7.2" tall. I would suggest that you DIY your lights and go with 3 lamps and reflectors on each side. The reflectors are usually 2.75 to 3" wide, so 3 wide would be about 8.25 to 9", I would try to find narrow reflectors in this case and make your "active" vertical screen area about 8.5 to 9" tall (add a little for the amount that gets inserted into the tube).

    So with a 22" long slot, you want 35 GPH, this works out to about 770 GPH, round that to 800 (because you're going to lose 15-20% flow in 6 months, before you clean your pump) and that works out to a 3000 LPH pump. So if you make sure to use the proper return hose size from the pump to the scrubber, your head loss will be minimal, and you could probably use a straight 3000 LPH pump, or a 3500 LPH pump with a valve to back it off if your flow is a little high, which you can open up a little each month to keep flow consistent between cleaning. Higher flow is just fine though so that might not be necessary.

    Also the acrylic enclosure will have to be well braced so that it doesn't warp from water contact and heat.

    Make sense?

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