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DIY Scrubber, just swap to LED

Discussion in 'Algae Scrubber DIY' started by Dota, Apr 1, 2015.

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  1. Dota

    Dota New Member

    hi, i hv my DIY scrubber for long time ago, but recently i just swap the T5 light to LED few weeks ago.
    but maybe my LED fixture is too strong, so lately, the algae grew very very thin... eventhough is thin, its GHA :D

    My Led Fixture : (3 x 10) @ 3W bridgelux LED
    My screen size : 50 Cm x 15 Cm
    My pump : lifetech 3900 LPH ( i'm sure, i have to re-check)

    at the moment i run 9 hr only, please give suggestion.

    Thank you

    Attached Files:

  2. Turbo

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

    Welcome the to site Dota!

    Ok, had to convert...6x20 = 120 sq in, big screen!

    120/30 = 4 sq in per LED, so that's on the "high" end of intensity

    How much do you feed?

    3900 LPH = 1000 GPH, but us that the pump rating or measured flow?

    Would you say your growth under T5's was better? Or different?
  3. Dota

    Dota New Member

    sorry, actually my LED fixture : ( 3 x 12 ) @3W bridgelux LED
    i ordered ( 3 x 10 ) but my friend gave me extra ( 3 x 12 )

    it was under normal T5 ( 4 x 14w ) was fine, but since lately i never change the bulb, so the algae doesnt looks growing very well, so i decided to buy DIY LED to get a Long 'n' thick GHA.

    " 3900 LPH = 1000 GPH, but us that the pump rating or measured flow? "
    im not sure what u mean ?

    i feed twice a day but just a little, pellet only let say about 4 to 5 pinch each
  4. Turbo

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

    What I mean is this: is 3900 LPH the maximum flow rating of the pump, or did you physically measure this (with a stopwatch and a container)? Every pump has a head loss curve. "head" is a term used to describe the "backpressure" the pump will have due to the distance is is required to pump. Most pump manufacturers provide or publish a head loss chart that you can use to estimate the actual flow you are getting.

    If your pump is dedicated to the scrubber, then you measure the vertical difference between the water level in the sump and the slot pipe, then add 24" for the slot pipe, and look on your chart to see how much flow you are getting.

    If your scrubber is fed off of the overflow from your tank, then your head loss is the vertical distance from the sump water level to the tank water level, plus a little bit more for any 90 degree elbows, etc.

    The point is that a 3900 LPH pump is what the pump will output at head = 0, and this is never the case unless it's just circulating water inside the tank

    Your scrubber is way too big for the amount you are feeding - so I think this is the reason for your low growth. That is perfectly fine, however, as long as the scrubber is doing it's job - growing algae, and keeping the nutrients in the tank low, etc.

    A few years ago, the guidelines were revised so that you could size a scrubber based on feeding instead of water volume of the tank. 12" of screen, lit on both sides, per cube of food per day. So your screen, 120 sq in, 120/12 = 10 cubes/day capacity. That's why I said it's huge. BUT: if your lighting is "below specification"...meaning, it doesn't have the wattage needed to match the screen size, then the screen's capacity is limited by light.

    So I'm willing to bet that your previous light fixture, 4x14 T5 (not T5HO, which would be 24W each) worked pretty good, because while your T5s were old, you didn't really need super-intense light because you weren't feeding a ton. The LED fixture, on the other hand, is super intense light. So that will tend to grow a thinner layer of algae, but it should be pretty dense and green - and that's fine.

    You can probably bump the hours back on the LED fixture to about half of what you are running now and get the same result. I would leave the T5 fixture photoperiod where it is though.

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