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Getting poor growth on new scrubber

Discussion in 'General Discussion' started by Radar1721, Mar 4, 2017.

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  1. Radar1721

    Radar1721 New Member

    Hi,
    I built my own scrubber and tried to follow the recommendations, but I'm not really getting any "thickness" to my growth four weeks in. I've got around 350 gph on a 10 inch wide screen. I'm using a 23w cfl with reflector on each side. The bulb is a little off center, but it is about 4 inches away. I might be a little low on light but I would think the parts closest to the bulb would grow differently if that was the case and they are not. I was running the light 18 hours a day, but I just recently dropped it to 12 to see if that would help.

    The nitrates in my 90 gallon are around 20. Based on my research I thought I would be seeing better growth by now. Do I just need to keep waiting? The uploaded sa
     
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  2. Turbo

    Turbo Does not really look like Johnny Carson Staff Member Site Owner Multiple Units! Customer

    Looks like your reply got cut off?

    So let's start with the basics and see if anything shakes out

    Screen dims? Length = 10", Height = ?

    GPH = 350, check. Is that your actual (measured) flow, or is that the pump rating? Or an estimate based on head loss? FYI, 35 GPH/in is no longer a "hard" number, it's a good target, but you can go lower also and get results

    Lamps: 23W CFL, check. Color temperature? 3500k, etc?

    Reflectors & proximity: need a pic of this, it really tells the story more than words. The lamp end on a spiral CFL can be the most intense and can photosaturate / inhibit growth

    Tank size: 90g, check

    Feeding? In cubes/day (frozen food) or an equivalent - list out what and how much you feed on an average daily basis, if it varies throughout the week, just list it all

    How long has tank been set up?

    Have a pic of the tank?

    How long has the scrubber been set up?

    How often do you clean/harvest the algae?

    How aggressively do you clean/harvest?

    Might have more questions, but let's start with that. I'm guessing you are the guy who posted on my FB page about the same issue? Glad you made it here, hope I can help!

    Bud
     
  3. Radar1721

    Radar1721 New Member

    I'll see if I can figure out how to make my pic smaller so it will upload.
    Length = 10", Height = 8

    This is the pump rating.

    Color is 2700k.

    The reflector is the stand clip on metal ones from Home Depot.

    I mix it up, but an average day will be
    1 cube of mysis
    Small sheet of nori
    2 pinches of flakes
    A few small pellets

    1 year

    scrubber has been running 4 weeks

    Once a week. The screen is completely covered with a base, but it hasn't grown "out"

    Spray it off and wipe it with my hand. There isn't much to come off.

     
    Last edited by a moderator: Mar 4, 2017
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  4. Radar1721

    Radar1721 New Member


    IMG_0052.JPG
     
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  5. Turbo

    Turbo Does not really look like Johnny Carson Staff Member Site Owner Multiple Units! Customer

    Ok - that appears to be the old volume-based sizing, which was 1 sq in per gallon of water. This is done by feeding rate now

    Algae Scrubber Basics - Planning Your Algae Scrubber

    Your flow is likely less than 1/2 of the pump rating once you factor in vertical head and plumbing losses - but that is not the biggest issue right now, and that pump might be OK if you reconfigure the scrubber

    The mysis and nori will be the biggest nutrient contributors. Can you be more specific on the nori? Like in square inches, approximately. Either way, the scrubber is huge compared to the feeding rate. This will cause the algae to "want" to "spread out" because the area is there, so it tries to cover it all. In doing so, it chokes itself off. The result is too much light, not enough nutrients, usually means gooey yellowish growth with maybe a few sprigs of green here and there (in "ideal" condition locations)

    it's still pretty young - if it was just roughed up canvas (no mortar coating) it takes 4-6 weeks before you could even expect to see the screen growth start to kick in. So don't judge prematurely, this is not an overnight process (the maturing of the screen)

    the "clean every 7 days" rule is out the window also, especially on start-up. Go 10 days minimum, 17-18 days max, and don't scrape or scrub at all for at least a month - just let it grow

    good - just don't use a kitchen sprayer or high pressure anything. room temp tap water, 1/2 way on, rub with fingertips. You want to remove any gooey yellow growth or stringy brown growth, but leave anything that survives that gentle cleaning alone

    This looks pretty decent for 4 weeks

    So back to the size, here's the thing - an oversized screen can be OK, or it can be problematic. It's hard to predict.

    Based on your feeding, which appears to be about 1-1.5 cubes/day, maybe 2 max, you only really need a 2 cube/day screen, which would be about 5x5. You have an 80 sq in screen which is more like 6 cubes/day. if it were me, I would downsize to a 6x6 or at the most a 7x7 screen, same lights, same pump (the GPH/in will increase), but that means cutting a new slot pipe, etc so that's your call. It might come in on it's own and do OK, hard to say. So I wouldn't say your build is way off track or anything, because it's too early to say that. But if/when it does start kicking in, and your nutrients get really low, you could start seeing that yellow gooey growth take over because of the size/nutrient ratio.

    Post pics of your lights, that's the last piece of the puzzle. reflectors and lamps, in the position you run them in
     
  6. Radar1721

    Radar1721 New Member


    IMG_0053.JPG
    Thanks so much for your replies. Attached is a pic of my lamp. There is one like it facing the other side. I don't have enough room to make it perpendicular to the face, but the distance is about right.

    My nori sheets are probably around 3x3, 9 sq inches.
    I sized the screen for the feeding I wanted to do, but I was hesitant to start putting more food in until I could see the nitrates start to lower. It sounds like you are saying I might need to monitor it for a few weeks to see how it develops.
     
  7. Turbo

    Turbo Does not really look like Johnny Carson Staff Member Site Owner Multiple Units! Customer

    You actually want it about 4" away and as perpendicular to the screen as you can make it. Where you have it is not a very effective position. It explains the dark growth, that is likely due to lack of intensity. The reflector is not ideal either but I think the solution here is to use a CFL floodlight instead, you can remove the reflector because you won't need it. The floodlight will give you a bit more of a focused spot, but I would use 2 per side so you can get better overall coverage since a floodlight covers about 5x5 pretty well
     
  8. Radar1721

    Radar1721 New Member

    Ok. I can try the floodlights. I had thought about that as a solution, but I had read somewhere they were ineffective. Do you have a link to a good socket I can use for the lights since I am taking out the reflectors? Lowes, Home Depot, or Amazon.... I'm pretty sure I saw the bulbs I need to get.

    Thanks
     
  9. Turbo

    Turbo Does not really look like Johnny Carson Staff Member Site Owner Multiple Units! Customer

    You can just remove the lamp and unscrew the reflector and keep using the clamp-on one you have. In thinking about it, you can probably leave the ones you have as-is and just get another set just like it and remove the reflectors and use floodlights.
     
  10. Radar1721

    Radar1721 New Member

  11. Turbo

    Turbo Does not really look like Johnny Carson Staff Member Site Owner Multiple Units! Customer

    Whoa that is awesome!!! Good find! I honestly didn't even think to look for something like that. I have all kinds of uses for it!!!
     
  12. Radar1721

    Radar1721 New Member

    Well, I have continued to stike out with the cfl bulbs. I can't manage to get a position in my sump where I can get the lights where they need to be. I'm going try the led route. There are many choices on amazon and I was thinking of giving this one a shot. What do you think? I should be able to hang this about 2-3 inches directly in front of my 10x10 screen.

    Amazon.com : ACKE LED Grow Lights Fixtures Plant Lights 24W for Plants' Seedlings Hydroponics Green House Aeroponics Herbs Veg. Flower (SMD with switch) : Patio, Lawn & Garden

    Any recommendations since there are so many to choose from on Amazon?
     
  13. Turbo

    Turbo Does not really look like Johnny Carson Staff Member Site Owner Multiple Units! Customer

    Not sure about that one, but the SMD LEDs like that tend to be not as effective. Although, things are changing pretty rapidly, there are new ones coming out all the time. This one is a style/layout I haven't seen before. They're using 60 0.5W LEDs which would be 30W but they say it's a 24W fixture that atually uses 20W. Chances are, the driver takes up ~5W and it's actually 15W of actual light power, if that.

    that's the problem with most LED fixtures - marketing vs actual.

    I wish I had more time to keep up on fixtures, but I just don't especially not at this point in time (work). You should be able to get production with CFLs though, if you are not, it's doubtful that things are going to be drastically different with LEDs. Even if you can only get growth to work right in a limited area of the screen due to the arrangement issue - you should be able to make it work at least somewhat.
     

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