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Algae scrubber not getting the growth I expected

Discussion in 'General Discussion' started by RIGFISHER, Jan 20, 2018.

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  1. This is what the screen looks like after 9 days I've turn the lights on 19 on 5 off and remove the shade screen I had how these things are going good but still not fast enough can I increase the amount of time the lights are on or should I look at getting better lights

    Attached Files:

  2. The algae is growing good but still not fast enough I wish I could go back and correct the post I put on they don't make sense sometimes sorry my nitrates are still around 40
  3. Turbo

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

    Sorry I meant to reply to these previous messages so thanks for updating the thread
    Usually, once you get the screen to fill in, you can remove the diffuser and it should remain filled in. Usually.
    I wouldn't think you would need a larger unit or stronger lights, if you've been running that for a year with 16 on / 8 off and diffusers in place, you have a lot of headroom to play with. You've removed the diffuser, so that is a major change. Adding hours is another.
    Let it grow longer - more time. As long as the lights are intense enough (yours are) to penetrate through the algae mat (which isn't that thick, so light getting blocked and not making it to the base or the screen is not an issue) then you don't "need" to harvest.

    Also, think "harvest" and not "clean". I would like to see one of your post-cleaning pics. You may be over-cleaning...which is why I've started to use "harvest". You want to leave a pretty decent amount of growth behind. One of the common misconceptions is that you want to fully remove all growth, and this really isn't necessarily true. You want to remove somewhere in the range of 75%.

    You may also consider doing intermediate harvests, where you take the screen out, rinse it and rub it with your fingertips to remove maybe up to 50% of the growth (a light scraping might be done, but in strips in an "X" pattern or "#" pattern) and then put it back in. The idea here is to just "prune" and then allow a fast recovery. This is especially helpful when you are dealing with long-term high nutrients, but you have a somewhat mature screen. This is sort of your situation.

    I think all you need to do is adjust your harvest method & frequency and then get aggressive with the lighting intensity and duration.


    1) don't over-harvest or over-clean
    2) this allows your screen to be able to handle the higher intensity light
    3) do only intermediate harvests every 7-10 days, maybe even 14 - don't do a "full" harvest for a couple of months.
    4) you've already increased intensity; so hold the hours and focus on doing #1 and #3
    5) you should start to see the growth bulk up a bit, and nutrients should start to drop.
    6) as long as #5 is happening, you can start adding hours - add 1-2 hours to your daily photoperiod once every 1-2 weeks. Once you get to 22 hours/day, hold there for a while and monitor things
    7) once you start to see nutrients really dropping, you may consider backing off on the photoperiod...you don't want to overshoot and bottom out the nutrients and cause the growth to reverse. I wouldn't expect that to happen, but you also don't want to intentionally cause that

    I think the root of your issue is likely cleaning too frequently, and maybe too aggressively. But - let me know if you think I've accurately described your process of cleaning, I've made some assumptions here - correct me if I assumed wrong, this might change my advice!
  4. Thank you for the reply yes you're pretty correct I clean the screen with a scraper where there is very little left on it just enough to stain the screen green so if I understand correctly you think I should just keep the lights I'm using now and just see how it changes play out
  5. Turbo

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

    Correct - you might try this for a while and see if you can kick-start the nutrient reduction: instead of scraping with a chiseling action - with the blade angled into the direction of travel - use a "dragging" action. This will sort of tear the growth away instead of actually scraping, and it tends to remove the outer layer while leaving more small stands attached to the screen.

    Also you can use the corner of the scraper to clear the growth off the screen more aggressively, but make an "X" pattern on one side (scrape lines about 1-2" apart) and then on the other side make a "#" pattern or tic-tac-toe pattern. So this way, you are removing growth completely, but only on one side. Then you will have parts of the screen that have growth removed on both sides (where the patterns intersect), growth on just one side, and spots with growth on both sides. This allows both light to get to the base (from both sides) and lets water get there too.

    These techniques generally result in no gap in filtration - the reason you might have elevated nitrates could be because when you clean too aggressively, you have little to no filtration, so the scrubber isn't ever getting caught up after this gap, and when it starts to, you clean it again.

    This should break the cycle. I would try these techniques first and leave the lighting where it's currently at (16-18 hrs/day, no diffuser)
  6. Ok thanks I appreciate the help
  7. Turbo

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

  8. Had the unit running about 2 years and it's been doing okay but lights were starting to go out and one of his burn out they do not make these lights any more so I replace them with new lights .now the algae is dark green very very dense with some brown on it been about 14 days since I put the new lights on do you think this issue resolved before I change the lights it look like standard hire algae growing on it.

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