Do Healthy Plants Release Organics?

Discussion in 'Water Chemistry' started by jaypeecee, 28 Nov 2019.

  1. jaypeecee

    jaypeecee Member

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    Hi @MJQMJQ

    I'm not sure whether it's polyurethane foam or some other polymer. Sorry to be pedantic but I would have thought carbon-impregnated foam would adsorb oils as opposed to absorb them. But, perhaps I'm wrong. That aside, you are obviously thinking on the same lines as me. Are you suggesting that polyurethane foam would work on its own, i.e. without carbon impregnation?

    JPC
     
  2. Iain Sutherland

    Iain Sutherland Forum Moderator Staff Member

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    I dont know if the carbon theory stands up... only on the basis that ADA superjet filters run only carbon as media, in the bigger ones several kgs, yet they still have skimmers running in all tanks in the ada gallery.

    It's weird you still have film after running the skimmer, even on my bigger high tech tanks all film would be gone in 15 minutes?
    If you mean that you turn the skimmer off and it comes back in an hour or so then that's different.
    The skimmer wont get rid of all surface scum as such, more that it keeps it in solution... the sponge does catch the initial film.. if you pull it out after 5 minutes you'll see the little sponge can have a white slime over it which is worth washing but leave it running and that slime will go back into solution.

    Sent from my SM-G950F using Tapatalk
     
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  3. jaypeecee

    jaypeecee Member

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    Hi @Iain Sutherland

    I just need to get used to this piece of kit. It's further complicated by the fact that I had to make a 'livestock protector'. I am fully aware that some people have had problems with the Eheim skim350 as it can suck in small fish, shrimps, etc. I am less than happy with some aspects of the mechanical design of this surface skimmer. But, it's probably the best of the bunch. My 'livestock protector' is a simple piece of plastic with many small holes in it. This does affect the flow - but only slightly. But, it's essential. One of my Panda Garras swam straight through the grooves in the skim350 floating structure. And that's a Panda Garra - approx. 6mm width!

    After playing about with this skimmer today, it sucked in the entire surface film in less time than it has taken me to write this post! So, like I said initially, I just need to get used to it.

    JPC
     
  4. jaypeecee

    jaypeecee Member

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    Hi @MJQMJQ

    I thought tea-stained water was caused by humic substances (HS). But there are many other compounds relevant to aquarists under the heading of DOC, aren't there? In a quick search online, I found the following:

    https://www.hindawi.com/journals/jchem/2016/1537370/

    It goes well over my head but it may mean more to @dw1305 .

    JPC
     
  5. MJQMJQ

    MJQMJQ Member

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    Humic substances contain many different substances some of which is DOC/DOM eg humic acid. The ones that contribute to the colour are tanninc acids humic acids and other such HS.Yes there are too many such compounds haha.
    DOC(dissolved organic compounds) are interchangeable with DOM(dissolved organic matter)
     
    Last edited: 2 Dec 2019
  6. dw1305

    dw1305 Expert

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    Hi all,
    That is a useful reference.

    DOC covers a whole range of substances and sources. If you collect a really nasty organic waster water (<"landfill leachate"> is the one I'm familiar with), it tends to be thick and black, with a high conductivity and an incredibly high BOD and TDS. It is really difficult <"to deal with">, because you have multiple issues.

    [​IMG]

    In terms of aquariums the important bit of the paper is:
    In <"tea stained "black water"> the tint is caused by relatively smaller organic molecules, these are often "aromatic compounds" (compounds that contain on or more <"benzene rings">).

    Aromatic compounds are generally resistant to microbial degradation (<"Bacterial Degradation of Aromatic Compounds">), and can accumulate over time. I just asked our environmental chemist to give me a proper explanation, and she says you need to look at the "activation energies" of the compounds, and that gives you a measure of their <"inherent biodegradability">. Activation energies are the "low hanging fruits" analogy in <"What is organic waste">.

    The researcher who has done a lot of work on humic, tannic and fulvic compounds is <"Christian Steinberg">, author of the standard reference <"Ecology of Humic Substances in Freshwaters: Determinants from Geochemistry to Ecological Niches.">

    I don't have a copy unfortunately, it is £200 as a hard-back.

    cheers Darrel
     
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  7. MJQMJQ

    MJQMJQ Member

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    I have a suspicion that plants are able to absorb these substances that cause black water in aquarium because the colour disappears after time without any water change.Otherwise degradation by light.
     
  8. dw1305

    dw1305 Expert

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    Hi all,
    I think it is a combination of <"bacteria, plants and light">. It is back to the <"shades of grey"> scenario, with synergistic effects and complex food webs.

    "Woody debris", like bog wood and structural leaf litter, degrades a lot more quickly in highly oxygenated, alkaline water and/or when you add nitrogen.

    This is caused by a range of factors, and is partially because invertebrate shredders tend to be a lot more common in alkaline conditions, and they are <"initially fragmenting the leaves"> to allow easier microbial decomposition.

    These processes can only occur if there is a high enough nitrogen to carbon ratio. We've recently been looking at a technique for estimating decomposition rates <"using cotton strips">.

    Any-one who has kept shrimps will have seen that IAL leaves etc disappear in their tanks, and even <"Alder "cones" degrade more quickly">.

    The build-up of tannic, humic and fulvic substances, in "black water" rivers, is also a nutrient effect. If you look at the <"conductivity values for the Rio Negro"> etc. there a very few ions of any description, and nitrogen (N), phosphorus (P), potassium (K) etc. availability limits microbial (and micro-faunal) break-down.
    cheers Darrel
     
    Last edited: 2 Dec 2019
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  9. MJQMJQ

    MJQMJQ Member

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    I believe if its more alkaline then the bases would react with acids which are commonly released by organic substances hence they would turn into other substances.Its the same for land decomposition too ideal ratio C:N is about 20:1.Extreme acidity will make it hard for even bacteria to thrive and "preserves" the material.
     
  10. MJQMJQ

    MJQMJQ Member

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    Apparently so at least for oil spills in the ocean I think.Activated carbon would probably be more effective due to more pores that can trap oils.And since the research papers say absorb well I would think it is.Just do yr maintenance from time to time to prevent oils clogging everything up.
     

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  11. jaypeecee

    jaypeecee Member

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    Hi Folks,

    A while ago, I discovered a paper by Dr Christian Steinberg. Here's some more bedtime reading for anyone who wants to delve further:

    https://onlinelibrary.wiley.com/doi/full/10.1111/j.1365-2427.2006.01571.x

    BTW, the link response time may be very slow but it's well worth the wait. The following snippet from this paper may well be of interest to those people who have cyanobacteria problems:

    "For instance, the presence of HS suppresses cyanobacteria more than eukaryotic algae".

    JPC
     
    Last edited: 2 Dec 2019
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  12. jaypeecee

    jaypeecee Member

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    Couldn't resist picking out the above statement. It's amazing how the IAL/Catappa leaves perform their vanishing trick. I presume the leaves would also do this in a 'fish only' tank?

    JPC
     
  13. dw1305

    dw1305 Expert

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    Hi all,
    I think they will, but presumably more slowly. Some leaves are a lot more persistent than IAL (Terminalia catappa). @Lindy comments on leaf longevity in <"Leaves & Gravel">.

    cheers Darrel
     
  14. jaypeecee

    jaypeecee Member

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    Hi @dw1305

    If this lipid/wax mixture could be sucked off the surface from above, then that may remove this film. It may require something actually floating on the water surface. What about a carbon-impregnated sponge? Or, a fine structure foam/sponge (with good capillary action). At least, it shouldn't sink! If I can find any of these things in my many bits'n'pieces drawers/boxes, I'll give it a try. One other thought - if this lipid/wax mixture naturally floats, then the likes of Purigen will never even 'see' it.

    JPC
     
  15. jaypeecee

    jaypeecee Member

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    Hi Folks,

    Please find attached my second attempt at a 'livestock protector'. It works pretty well. Why Eheim could not have included a suitable protector, I just don't know. The photograph shows the top of the floating section of the skim350, i.e. the inlet (obviously not in situ!).

    JPC
     

    Attached Files:

    Last edited: 6 Dec 2019
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  16. jaypeecee

    jaypeecee Member

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    Hi Folks,

    At the moment, this surface skimmer is doing an excellent job. No oily film whatsoever on the water surface - it looks like a mirror (from above and below the surface). Fingers crossed that I can keep it like this. And I can now maintain tighter control on dissolved CO2, which was the main driver for doing all this in the first place!

    JPC
     
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  17. Zeus.

    Zeus. Member

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    and better O2 uptake at night ;) better O2 uptake better for inmates and canister filter media bacteria
     
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  18. jaypeecee

    jaypeecee Member

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    So true. But I was getting seriously concerned about the dissolved CO2 level. Even the DC was moving towards yellow - but never got there.

    JPC
     
  19. Thumper

    Thumper Member

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    Green Aqua sells a 3D printed protector which replaces the top part. Works fien for me since a few weeks.
     
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  20. Oldguy

    Oldguy Member

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    I like to think of Activation Energy as the size of the brick behind the wheel of a car ( with no brakes) parked on the side of a hill. Spontaneous reactions just have Activation Energies lower than that provided by ambient temperatures, very tiny lego bricks.
     
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