Skimming

Discussion in 'Protein Skimmers, Mechanical Filtration' started by Graham, 2 Apr 2008.

  1. Graham

    Graham

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    Hi guys

    Can a person overskim? I'm new - forgive me if the question is stupid or has been covered previuosly. thanks
     
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  3. Mike

    Mike Retired Moderator

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    Overskimming is generally considered better than underskimming, most reefers tend to buy a skimmer rated 1.5 or 2 times the capacity of their tanks, it will do much more good than harm.
     
  4. jacquesb

    jacquesb Retired Moderator

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    Hello Graham - there's no such question as a stupid question - only the question not asked ;-)

    This is a controversial topic. Most answers you will most likely get, is NO. You cannot OVER-SKIM. BUT, I had an interesting conversation a few times with some reefers.
    The thing is - sometimes if a skimmer is REALLY big, you sometimes take things out of the water that your corals would prefer to "eat". Then, it ends up that you have to doze/feed the stuff that was originally in the water in the first place.

    Look - nearly everyone on this site knows - I SCUBA dive - and I have NEVER seen any true natural reef, that is as clear as people keep their tank water (especially the people who have HUGE skimmers, and mostly keep SPS corals)....

    Personally - I would rather opt (for my own tank/s that is) to share the filtration in my system with a HUGE DSB (deep sand bed), and a reasonably sized skimmer....

    BUT that's me, hey.... My personal opinion of the skimmer is: that it is a failsafe mechanism that is there to quickly remove crap from the water for in case something might go wrong.... As a skimmer quickly removes crap (DOC's, POC's, ammonia, possibly organic phosphates, etc) from the water, it can save your life stock for example if you have a fish or coral die on you.
    BUT - a DSB works a lot better, together with a algae scrubber (natural filtration methods), but slower.....

    As I said - wait for the others to comment - they could quite possibly have different opinions to me ;-)
     
  5. Graham

    Graham Thread Starter

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    Thanks
     
  6. Mike

    Mike Retired Moderator

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    Oh and Graham, welcome to the forum mate, glad you joined us
     
  7. Graham

    Graham Thread Starter

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    Cheers Wee Man
     
  8. Kanga

    Kanga Retired Moderator MASA Contributor

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    Welcome Graham, although I do think overskimming is possible, it is so very unlikely unless you have a few monster skimmers on a small tank


    This in a 4ft tank might be overskimming, ......possibly

    [​IMG]
     
  9. gaboon

    gaboon

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    Kanga, I never gave you permission to post a pic of my skimmer:)
     
  10. sunburst

    sunburst

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    Chuckle chuckle. Welcome Graham. Over skimming mmmmmmmmmaybe not.
     
  11. shan

    shan

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    kanga - that skimmer holds more water then a 4 ft would ...lol
     
  12. Mekaeel

    Mekaeel Moderator MASA Contributor

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    ok the skimmer im gonna be using on my new tank which is +- 800L is a DNW 300 and might just hook up my DNW 200 aswell.but this tank will be filled with SPS.planning a heavy bioload
     
  13. Midasblenny

    Midasblenny

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    I do believe one can overskim a system but as mentioned go for one rated for twice the water your tank holds and thats as far as i would go.
     
  14. jacquesb

    jacquesb Retired Moderator

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    Mekaeel - define "heavy" bioload? Do you mean "heavy" like in a LOT of fish? Can corals count as a "heavy bioload"?
     
  15. sunburst

    sunburst

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    Hmmm...mine is rated at six times tank capacity. Is this belief of over skimming from personal experience or from word of mouth or popular internet forums.
    I do not know any one who has ever claimed that skimming caused a downward spiral of their marine eco system.
    From my personal experience, i have found that when there is nothing left to skim... the skimmer stops skimming. Period.
    However the benefits of supercharging your water (redox) has enormous benfits.
     
  16. Mike

    Mike Retired Moderator

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    I think it's the fish that shit a lot that causes a heavy bioload as opposed to corals:whistling:
     
  17. jacquesb

    jacquesb Retired Moderator

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    Wee-Man - you SO right. BUT, extraneous feeding of corals can also cause polution.

    Sunburst - I don't overskimming is always clearly defined. Personally, I don't think it's a case of not being able to remove ANYTHING from the water anymore, because as long as the are living organisms in the water, some form of DOC's and proteins will be in the water column..... And as such, your skimmer will skim.... Probably a bit slower perhaps than with a heavy bio-load.....
    The point I think that I have had discussions with a few people with, is the fact of HOW MUCH "coral food" one would be skimming out of the water when you have a HUGE HUGE HUGE skimmer?
    Do you have to feed extra coral food to keep your corals happy? (IF you do not have 400 watt metal halides - that is - then your corals will "feed" off the food produced by the zooxanthellae....
    BUT even the zooxanthellae MUST live off something, right? What do they live off? Nutrients in the water column?

    If you skimmer removes ALL nutrients, and proteins, and you don't feed your corals - what do they (corals/zooxanthellae) live off?

    Then - there's the fish..... feeding the fish produces waste, waste produces POC's/DOC's/nutrients.....

    So - my theory is - bigger skimmer - more fish - more waste - bigger skimmer required....

    I could / would be wrong..... Have been before.... Am I wrong?
     
  18. Mike

    Mike Retired Moderator

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    Jacques, don't forget the skimmer can only skim what goes over the weir, nothing else can be skimmed so the excess nutrients (for want of a better term) will be in the water column for some time before they work their way up and out of the tank and into the sump (assuming that is you set up - which i think the majority are) so i'm sure the corals will have some chowing time before the skimmer can get to work.
     
  19. jacquesb

    jacquesb Retired Moderator

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    Quite correct Wee-Man. Thanks. BUT - don't this also depend on the water flow cycle that someone's tank has? Won't this also depend on the amount of water going doing the over-flow, into the sump, and back up to the tank?

    BUT - I see your point. There SHOULD always be nutrients in the water...
     
  20. Midasblenny

    Midasblenny

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    Speak to Bob the reef builder who lost practically the entire system of healthy sps when a monster (10ft) skimmer was added.
    I underskim, 2000l system witha skimmer rated for a 1000L running wetish so the cup fills daily, awesome sps colours due to this.
     
  21. Midasblenny

    Midasblenny

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    Corals also wee-man, we have a few propagation systems with no fish and skimmate is just as pungent and dark as my reef tank with 45 fish.
     
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