+ Reply to Thread
Page 1 of 3 123 LastLast
Results 1 to 10 of 22

Thread: Questions after 10 months scrubbing

  1. #1

    Join Date
    Jan 2009
    Posts
    49

    Questions after 10 months scrubbing

    I've been running a skimmerless reef with a scrubber successfully for 10 months now. I have experimented as I went along, and would like to question some of the accepted methods used. I realise that often things that happen are specific to ones own system, and would therefore like to hear what others have to add to my observations.

    The biggest discrepancy I have is that I feel that the screen only really kicks in after there is a weeks worth of growth on it. It seems that less water runs over the algae, but rather through it, once it is denser. This continues for up to 3 weeks of growth, when it really does become high time to scrape the screen as light penetration becomes an issue. I grow the screens between 2-3 weeks and have never had an issue of the lower levels of algae dieing and releasing posphates back into the system.

    Pods eating algae? It has never once been an issue on my screens. If they do eat it, they have never left any holes in the screen. Which brings me to my last point. Why on earth would we want to clean our screens in fresh water? This sets the algae growth back by 24-48hrs in my estimation. I'm gaugeing this on the oxygen bubbles that form amongst the photosynthesising algae. It take 2 days before I see any bubbles after a fresh water cleaning. After rinsing in saltwater, there are bubbles present within hours again. Pods are present in the scrubber area all of the time, and move around very rapidly, so rinsing the screen in fresh water does not help, as new one will jump right back on as soon as the screen is replaced. Anyhow, the large ones that could possible eat enough algae to cause an issue(and I doubt this) have already been scraped away with the algae.

    I'm currently experimenting with optimum lighting periods on the screens and will post on this once I have results. I want to see if 18hr on/ 6hr off is the ideal period, or if the algae continues useing nutrients in the dark phase as well, and where a 12 on/12/off cycle wouldn't be better.

  2. #2
    kcress's Avatar
    Join Date
    Nov 2008
    Location
    Santa Cruz, California, USA
    Posts
    458

    Re: Questions after 10 months scrubbing

    Thanks for the observations!

    I would tend to collaborate your findings. I have had zero pod issues even with a huge pod loading in the tank - really huge. I have never found pods to care about any macro algae. They are very persnickety. They even have major preferences. Greatly preferring red micro algae to green micro algae.

    Real ocean turf gets fresh water rinses. I have done many FW rinses (with chlorine) and never seen any obvious inhibition. I will admit to never seeing any bubbles form because I never expected to see any in the furious surface flow.

    Are there any pics of your scrubber about?
    Do you have any close ups of the flow/bubbles?

  3. #3
    Super Moderator
    Join Date
    Oct 2008
    Location
    Santa Monica, CA, USA
    Posts
    9,712

    Re: Questions after 10 months scrubbing

    Good observations. All have been thought of and tested to various extents by other folks here and there, but the current recommendations were established to help most of the people most of the time (especially first-time scrubber users). As you mention, certain tanks will have variations, like yours (especially after maturing), and when you get enough experience, it may help to alter things.

    The number one problem that occurs with most new users on every site is building the scrubber and then just letting it "sit" until it "looks full of algae". And by algae, they mean "nice fluffy green stuff". Scrubbers rarely start out green, and certainly don't get thick and full in the first cleaning period. So what has to be avoided, is letting the beginners think "it just needs more time to turn green and thick". Because if they wait, the pods kick in, the bottom layers kick in, and then they end up with cloudy colored water, and worse nutrients than when they started. I've seen it hundreds of times. Happens on every site.

    Your scrubber has a few particulars which make it different from most: Very strong lighting, and very good flow. Here is how that alters things:

    Growth time: In your case, the strong flow and lighting cause very rapid growth of the top/new layers. So yes you get good filtering for more than one week, because just as the bottom layers are starting to slow down/die, you have three fresh new layers to make up for it. But most people don't have such strong lighting, and possibly also their pipes get clogged quicker (so less flow too). So they won't get the rapid new top layers to make up for the dying bottom layers. (My scrubber will go longer than a week too, but I'm running 100W on a screen that is just 5 inches tall, and just 1 inch away, so the rapid growth outpaces the dying layers.)

    Another big pitfall is systems with high nutrients (which is most tanks with a new scrubber). These tanks grow the dark/oily stuff to begin with, which only gets to be 1/8 inch thick or so at best. Bottom layers start dying in just a few days, because all light is cut off. So if let to "grow" for a few weeks, it's a certain failure. So by making sure the screen is cleaned every 7 days, you eliminate problems in all of the the under-lit, under-flow, and/or oily-growth scrubbers. And this is why everyone who runs their scrubbers under the 7-day recommendation get good results. Not stellar results, like yours, but good. In your case, since you know what to look for, and you know how to tell if your nutrients are rising or falling, you are in a safe place to experiment, ESPECIALLY since you began your scrubber last year using the basic recommendations.

    Pods: The original recommendation of using FW came from Inland Aquatics, who had been running scrubbers for ten years previous. So I started with that. This, combined with the fact that you need to remove the screen and clean it somewhere besides the tank, led to the FW-in-the-sink recommendation. Everyone has a sink, so it works good. But as for the effects of pods, remember that they are in the algae for a reason: To eat it. This eating starts out small, with just a few thousand white specs (baby pods) scattered across the screen. They are only eating a little, but the rapid new growth on the the top layers more than makes up for it. After a few days, however, there are millions of pods, and this is when they consume enough algae to out-pace the new growth of the average scrubber. You don't "see" any of this though, because each pod's effect is invisible; it's just evenly spread throughout the algae. It's not until the last stage of pod growth, where they multiply in groups/colonies/localized areas, that visible "holes" are found. And even this is only visible when it's actually on the screen; if it's "in the algae", then it just get covered by other algae. Indeed, I've seen many new scrubber users baffled when their scrubbers don't work; and when they post pics, there are 3" round holes of bare screen, and they say "It's had 4 weeks to grow already, and it's still not working."

    So, we're back to your high-powered new growth greatly out-pacing the effects of the pods. It just so happens that your particular scrubber takes three weeks before the effects catch up. For the average scrubber, it's much sooner. And this is again the reason for the 7-day cleaning recommendation; it works for everyone. And the FW makes sure that the groups/colonies/localized areas are wiped out.

    Lighting: Many people complain of having to run a single 23W bulb, much less two of them (much less 4 X 45W that you have.) So the 7-day FW rule keeps thier pod and die-off effects from overcoming their (slow) new growth. And this is on top of them having flow problems. And as for the OFF period, 18/6 is actually not the best, it's just the easiest. The "best" is 3 X 2hrs OFF, or 6 X 1hr OFF. Studies (non-scrubber related) have been done to confirm this. Turns out that most of the respiration that is occuring in the OFF period actually happens at the very beginning of the period, and trails off from there. So most effective is to keep it short, more often. But of course for the typical new user, especially those with bedroom or living room tanks where you can see the scrubber light, this can't be done.

    Anyways, experimenters will experiment, and that's why scrubbers are here in the first place, so it will be nice to see what specific things help your system perform better.

  4. #4
    kcress's Avatar
    Join Date
    Nov 2008
    Location
    Santa Cruz, California, USA
    Posts
    458

    Re: Questions after 10 months scrubbing

    Thanks SM for the detailing.

  5. #5

    Join Date
    Jan 2009
    Posts
    49

    Re: Questions after 10 months scrubbing

    Thanks again for all of your effort Santa Monica. Without your perseverance, I would never have ventured down this road. Your explanations clear up any questions I had.

  6. #6

    Join Date
    Dec 2008
    Location
    USA
    Posts
    89

    Re: Questions after 10 months scrubbing

    I thought that the pulsing flow had a lot to due with the usage of light? I see now that SM says it isn't worth the time to put a scrubber on a pulsed flow. I read in dynamic aquaria that the pulsing of the flow acts as a light flasher. Which goes hand in hand with small ammounts of light more often.

  7. #7

    Join Date
    Jan 2009
    Posts
    49

    Re: Questions after 10 months scrubbing

    Quote Originally Posted by SantaMonica
    And as for the OFF period, 18/6 is actually not the best, it's just the easiest. The "best" is 3 X 2hrs OFF, or 6 X 1hr OFF. Studies (non-scrubber related) have been done to confirm this. Turns out that most of the respiration that is occuring in the OFF period actually happens at the very beginning of the period, and trails off from there. So most effective is to keep it short, more often.
    Do you have a link where I could read up on this, so that I can optimalise the experiment that I'm performing? I'd like to use the intervals as you describe, weighing the dried harvest over an 8 week period. I'll then use the 18/6 period as the control for a further 8 weeks. Do you see any room for improving the experiment? I'm starting with new lights, and will keep feeding as even as possible, obviously not adding any new livestock or changing any other parameters.

  8. #8
    kcress's Avatar
    Join Date
    Nov 2008
    Location
    Santa Cruz, California, USA
    Posts
    458

    Re: Questions after 10 months scrubbing

    I would say that you should change nothing for 2 weeks then do a 4 week study. Then change your light period to whatever, and then wait 2 weeks to allow any physiological changes needed by the turf to align with the new lighting, before the next 4 week study. If you just change it the turf may stumble for a week before adapting to the new light and this would skew your results.

  9. #9

    Join Date
    Jan 2009
    Posts
    49

    Re: Questions after 10 months scrubbing

    Quote Originally Posted by kcress
    wait 2 weeks to allow any physiological changes needed by the turf to align with the new lighting,
    Thanks kcress. I have to do that anyway as I have a 2 screen scrubber. I think though that any new algae would be instantly "aligned" to the new light provided. I would think that the only thing that a particular species of algae may expect would be the usual daylight pattern, light intensity and spectrum of it's natural environment. It would be interesting to hear from any horticulturists out there if the plants do develop some sort of "memory" regarding light period.

  10. #10
    Super Moderator
    Join Date
    Oct 2008
    Location
    Santa Monica, CA, USA
    Posts
    9,712

    Re: Questions after 10 months scrubbing

    I'll try to find it. I ran across it before I started keeping track of research.

+ Reply to Thread
Page 1 of 3 123 LastLast

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts