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Thread: help-super slow starting new scrubber

  1. #11

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    Apr 2009
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    Re: help-super slow starting new scrubber

    I'll get a shot of the flow as soon as I get home.

    The bottom 4 inches or so of the screen is in the water. The remaining 10-12 inches stays above the water. The algae line is right in the middle, about 6 inches from the top. Note, I am getting algae growth on the top half, its just "very" slow. The bottom half you see came in over the last 4-5 days. The top half has about 1/10 the amount, thinly growing.

    The lights: I want to say they're about 4 inches from the top of the pipe. Maybe 6. I clamped them on 6 inch tall clamps and pointed them down. The lights are 23 Watt, 5100K compact fluorescents "full-spectrum", 1 on each side of the screen.[attachment=0:31hwj9el]IMG_0191.jpg[/attachment:31hwj9el]

    Could flowrate cause this kind of problem? I have a 300gph overflow box, but I'm sure it's not flowing that fast. If I had to guess I'd put it at 200 gph (I know, I know, I have to time it tonight). My screen is about 8 inches wide, so I need 280 gph. :?:
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  2. #12

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    Oct 2008
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    Re: help-super slow starting new scrubber

    Ideally you want 35gal/h per inch of width, so 350gal/hour for 10" wide, but you'll find it's nowhere near that when you actually measure it.
    It'd be worth measuring the rate by filling a bucket.
    the 5100k bulbs are a bit too full spectrum, but they should work better than they have, I doubt it's any UV from the bulbs then. Normal cheap bulbs should be fine (around 3500k).
    How fast and even is the flow?

  3. #13

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    Dec 2008
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    Rowland Heights, CA, USA
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    Re: help-super slow starting new scrubber

    What I am guessing the cause of that line of algae growth might be from the pipe. Since the lights are mounted so high, can the pipe be actually acting as a light shield? I mean that is the only other thing I can imagine that would give a straight line like that. Coz that's how my screen look after I added a light shield to prevent algae growth into the slots.

  4. #14

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    Apr 2009
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    18

    Re: help-super slow starting new scrubber

    So I was right.
    I timed it and my flowrate is 200 gph. I raised the pump speed and water lever a little (variable speed pump) so I now estimating around a 220-230 gph rate, but lets stick with 200gph.

    Now, the top section is now semi covered with algae. There are clean patches, like some of the bottom, but it's there. The funny thing is the thickest patch of algae is along that center line we see.
    The bar-shading is an interesting idea. The lights are above the bar at an angle that could be reducing the light hitting the top. I'm getting smaller, better reflectors and clamps to lower the angle, so we shall see.

    The slow rate of algae growth has me baffled. This is the third week, and there's only a light covering on the screen. I expected to be scraping by now.

    Let's see what happens next.

  5. #15

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    Oct 2008
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    Re: help-super slow starting new scrubber

    Is there any way you can get the flow up to 350 gal/hour?
    Getting the smaller reflectors so you can get the lights closer should help. Also, you really should be doing a scraping once a week even if there's little growth, just use your hands to pull off what comes off easily.
    Also, do you rinse the screen under fresh water after cleaning?... Which is a stupid question as you said you haven't cleaned it...
    Clean it, rinse it, could be copepods eating the algae.

  6. #16

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    Apr 2009
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    Re: help-super slow starting new scrubber

    I am getting a new overflow box with a greater speed (600 ish). With my return pump this should get me into the 300's.
    And I'm getting new reflectors today, so this will help me direct the lights better.

    As far as the scraping, my understand was that I should let the screen sit until I start getting green algae. Currently I only have the brown type algae. Shouldn't I wait? I wouldn't be doing a scraping now as much as a wiping off.

  7. #17
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    Re: help-super slow starting new scrubber

    Wrong wrong wrong. Never let it set more than a week. The brown stuff must come off several times before the green will start.

  8. #18

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    Apr 2009
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    Re: help-super slow starting new scrubber

    Thanks. Will be done asap.

    On a positive note, the whole screen is covering up now, and the lights are lower and more focused directly onto the screen.

  9. #19

    Join Date
    Apr 2009
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    Re: help-super slow starting new scrubber

    So here's an update.

    My flow has become pretty steady. I'm flowing at about 300 gal/hr.

    My algae growth has also improved. That horizontal line is still the center of growth (very strange). I cleaned one side, and the regrowth began along that line and then spread outwards. The good thing is that growth is faster. Within a couple of days the cleaned side was full and becoming heavy again.

    I've just seen green algae growth begining in a couple of spots, which is a positive thing. It's amazing how clearly the grean algae comes in.

    I've also shifted my lights and added 2 more reflectors on the open sides to provide a more focused and even lighting into the bucket. This I'm sure has helped with the growth.

    Now for chemicals: I'm not sure if this is wishful thinking or direct results, but my Nitrate is staying consistantly in the mid to low forties between water changes. Before starting the srcubber I had large swings, with high thirties after a change to the fifties after a week. I actually peaked at 61 about 5 weeks ago.

    My Nitrates haven't gone past 45 in the last 2-3 weeks and the swings are smaller. I'm taking it as a positive note. I have 180 sqr inches of sheet (180 gals capacity) and my system is only 80 gallons, so it's possible the affects are currently noticeable.

    More to come as things evolve.


    And here's one more positive observation I've had. POWER OUTAGE EMERGENCY PLAN IMPROVEMENT. With the ATS and 2-3 marine batteries (approx $100 each) for the pump I can keep water flow and filtration going for up to 2 days if I have a power outage. Lighting is different issue, but the coral should be able to handle a couple of days with minimal lighting in an emergency.

  10. #20
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    Re: help-super slow starting new scrubber

    Good to see nitrate coming under control. Sound just about right. In time will start coming down.

    As for power, if you are home and the power goes out, you can just lay the screen in the water; it can sit for three days with no harm. But if you want filtering to continue, you'll need to power the pump. Algae keeps filtering (but not as much) even with the lights off.

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