Anaerobic areas - good, bad or indifferent?

Discussion in 'Substrates' started by nry, 2 Nov 2007.

  1. nry

    nry Member

    Messages:
    1,239
    Location:
    Cumbria, UK
    I stripped down my 15-gallon tank last night, taking out all the substrate ready for new stuff. I noticed a ~6 inch sq. area which was pretty dark and a bit ponky - I assume this was an anaerobic area. I had a similar thing when I stripped down my PFK Cube a while ago.

    In a heavily planted aquarium it is pretty hard, if not impossible, to disturb the substrate regularly - are such patches something to be concerned about long term or are they a natural thing that just happens? Can't say I have had any plant or fish related problems in either tank...the 15-gallon had been set up for ~18 months,the PFK cube for ~5 months.
     
  2. beeky

    beeky Member

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    879
    Location:
    Chippenham, Wiltshire
    I've got silver sand in low tech 2' tank with lots of crypts and haven't noticed any anerobic areas at all despite what I've heard about sand substrates. Does gas escape when you disturb it? Could it just be algae? BGA? If you've got a humus rich substrate, it's supposed to rot and cause anearobic areas. What substrate is it?
     
  3. nry

    nry Member

    Messages:
    1,239
    Location:
    Cumbria, UK
    The 5-gallon had JBL AquaBasis Plus covered with Hagen Black River Sand, but a fair depth of the sand, maybe 3" at the back.

    The 15-gallon had JBL AquaBasis Plus topped with pea gravel, about 2" gravel, likely a bit less.

    The 5-gallon did smell bad when I removed the substrate, doubt it was algae. The 15-gallon had a 6"x6" area in the middle of the tank which was dark, again smelt a bit bad - I think this may have been an area previously covered with rocks/wood.
     
  4. beeky

    beeky Member

    Messages:
    879
    Location:
    Chippenham, Wiltshire
    The BGA I had a while ago smelt terrible, a really acrid smell. My wife had to leave the room whenever I tried to clean the tank!

    You could try just disturbing the area a couple of times a week. I sometimes use the pointy bit of my algae scraper to poke things in the tank.
     
  5. bugs

    bugs Member

    Messages:
    356
    Perhaps this is where an UG heating cable may prove useful?
     
  6. Dan Crawford

    Dan Crawford Founder Staff Member

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    Location:
    Daventry, Northants
    oooooo, now youve gone and done it! lol.
     
  7. bugs

    bugs Member

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    356
    You gotta admit, it's an avenue worth exploring... Everyone is quite nonchalant about their preference to use or not without really being able to substantiate their reasons other than to usually state that the plants just seem to grow fine without, therefore, why bother. I would agree that plant growth may not be influenced by the cable, however, it would be interesting to see if it reduced anaerobic conditions.

    Would the addition of a heated cable make a "High-Tech" tank "Super High Tech"? Ooh, but "Low-Tech" (but not in derogatory sense) also like a bit of heated cabling so that would have to be <ponders>... "Low-Tech Plus". Or is "Low-Tech Plus" Low-Tech with EI or is that El Natural Ei?
     
  8. ceg4048

    ceg4048 Expert/Global Moderator Staff Member

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    8,937
    Location:
    Chicago, USA
    It seems to me that having plants grow fine without the use of cables is a substantial enough reason to avoid them. There are so many more factors involved in getting the plants to grow fine and to reduce algae that the absence of any definitive proof that they actually work is a major deterrent to their use. 20 years ago Dennerle and Dupla tried so hard to get everyone to use these cables. The propaganda at the time was that the plants got a better start and rooted more easily at tank startup. This was proven false by most everyones experience. The claim was then changed some time later to "the long term stability of the tank was improved". Most scoff at this as well.

    I think that plants which grow well and which develop sufficient root structure do a fair enough job of oxygenating the substrate. I've read where the plants actually are capable of transporting oxygen down to the roots. Additionally, there are reportedly enough thermal and osmotic gradients in the substrate to generate sufficient flow around the roots without the use of cables.

    What happens if it turns out that heating cables actually marginally degrade plant growth? What happens if it's shown that the extra thermal currents are too high and that they rob the roots of nutrient contact time?

    I've used both methods and have not seen any visible improvements using the cables and neither have I experienced the motley patches described by nry. Without a chemical analysis of the patch there is no way to determine what condition is being experienced so I wouldn't automatically call heating cables to the rescue. The patches described could easily be the overlooked and decayed root remnants of dead plants for example.

    It's easy to throw technology at a tank and to have it be ineffective or even counterproductive. I'm not implying that one can't grow a nice tank using this feature, it's just a matter of effort versus results. Why would you want to deal with the hassle, cost and ugliness of cables when in 20 years no one, including the manufacturers, has been able to demonstrate any definitive advantage?

    Cheers,
     
  9. George Farmer

    George Farmer Founder Staff Member

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    7,089
    Location:
    Cambridgeshire
    Substrate heating may well help to prevent excess anaerobic areas.

    But I'd rather have enough plant/root growth to avoid it in the first place, personally.
     
  10. nry

    nry Member

    Messages:
    1,239
    Location:
    Cumbria, UK
    I do feel that the substrate depth in the 5-gallon (which I am convinced did have anaerobic areas and not BGA) was partly to blame. The tank was mainly planted with vallis and did have a fair amount of root growth.

    Overall neither tank has had problems with plant growth or health, and given the complete lack of decent evidence for heater cables I had nore have any thoughts on buying one. Also they're just something else to go wrong - plus how do you know if they have gone wrong?......
     
  11. bugs

    bugs Member

    Messages:
    356
    It seems that nobody can deny that a heated cable may make a difference. The whole area is surrounded by opinion, conjecture, and absence of fact for or against the claimed or incidental benefits (or not).

    Both of my previous posts have been borne out by the subsequent comments.

    I think my work here is done...
     
  12. Ed Seeley

    Ed Seeley Member

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    3,262
    Location:
    Nottingham
    Yes, but the real question should not be do heater cables stop anaerobic areas, but do anearobic areas actually make any difference to the plants or fish? I've never used a cable and I would assume that small areas of my substrate have become anoxic, if not anearobic, therefore, IME, it doesn't make a difference.
     
  13. bugs

    bugs Member

    Messages:
    356
    But that then leads to yet another question to support the basis of your question, or more the point your observation that it does not make a difference... You based the outcome of your experience on an assumption that you have anaerobic areas. If, in fact, you don't have anaerobic areas then your observations and experience could be wrong.

    To even come close to identifying whether or not a cable makes a difference we would need more people using cables to compare to those that are not and be looking specifically at substrate condition upon stripdown after a matching time period. And have sufficient numbers of people involved in a controlled experiment for the numbers to be meaningul. Plus a few other variables to refine the data. We would also need to be able to accurately recognise the anaerobic state. Alternatively, if someone has access to a lab and a real scientist...

    This is a knotty issue and one we're not likely to resolve without keeping open minds to all possibilities. There's a real risk that only one version of success will be determined by people following a formula based on the experience and opinion of others - there seems to be a dwindling readiness to challenge and experiment with new ideas or reviewing previous opinion which could have simply been self-perpetuating. After all, the world IS flat...

    Sure, we could all have beautiful algae free aquariums and we could believe that they crash, get algae, and need a stripdown after a period of time because the substrate is "exhausted". What if it were something else that causes this phenomenon? What if it were anaerobic substrate?

    Do we just accept things because it seems the majority norm, supported by opinion, experience, and conjecture? Or do we keep the open mind that provides the framework for experimentation?
     
  14. Ed Seeley

    Ed Seeley Member

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    3,262
    Location:
    Nottingham
    I totally agree with you about keeping an open mind and I'm sorry if my response came across as being against that. Personally I don't think cables help as I have a number of aquariums that are supposed to 'need' cables (soils substrate and long term sand and other substrates) yet they do great without them. I'm not into EI and regularly changing everything either - purely becuase it doesn't suit me or the fish I keep.

    I don't think it can possibly be the case due to various physical laws of diffusion that the O2 concentration in an area of significantly lower flow, such as a sand substrate, can have an O2 concentration equal to that of the water column therefore partial or complete anoxia is probable, but, I agree, not proven.
    I'm merely assuming that I MAY have anearobic areas due to reduced water flow and bacterial respiration utilising O2 in the substrate leading to anoxic, or partially anoxic, areas possibly present in the substrate.
    If they are present they don't seem to be causing problems. And, if they aren't then I don't need a heating cable to get rid of them...

    Slightly take issue with the last sentence, but never mind...
    To empirically prove whether a cable will help or not you are completely right would take lots of independently verifiable tests where the only dependant variable was the prescence or abscence of a cable. Rather hard to do in this hobby unless someone has 20+ tanks going spare and the same room and conditions to remove other independant variables...

    Therefore we have to rely on people's experiences to see what happened when they tried out X, Y and Z. Not perfect, but not completely useless either.

    I'd like to think no-one here would say something, such as cables, definitely don't work. I certainly would never say that. All people have ever said here, to my knowledge, is in their experience there is no benefit in adding them. Surely that can't be a bad thing?

    Oh and I really like the Flat Earth Society reference but if you check out the horizon when you next go to the coast, you'll see the top of the ships on it first ergo the earth must be curved, or you'd see all the ship, just very, very small at the same time! ;) :D ;)
    Evidence is the over-riding imperative and always should be.

    You could well be right with the anearobic substrate idea. But will heating cables stop an anearobic substrate? Where's the evidence for that? And if stopping anearobic conditions is so vital why don't undergravel filters work really well for planted tanks too?

    In my opinion I agree that we should never accept things that people say on face value and going "with the majority" is just as bad in my opinion. We should listen to their experiences, consider their conditions and put all of that into the balance when deciding what to do. To take any person's 'method' as THE way to do something is, in my opinion, wrong and naive. Personally I can't get EI to work for me. I'm sure it works for others, in fact I've seen the tanks where it does, but for me - just doesn't work out. My experience may therefore be in opposition to many on here, but it's still valid surely? An open mind should be paramount, but maybe cables don't change things really either...

    And finally, wouldn't the world be a boring place if we all agreed all the time. I hope you enjoy a healthy debate as much as me and it can be a real mechanism for good thinking IMO. Please don't take any of my comments as being negative towards you - I appreciate why you have made the comments and I hope you can appreciate mine.
     
  15. JamesC

    JamesC Member

    Messages:
    1,276
    Location:
    Bexley, Kent
    Anaerobic conditions are normally caused in aquarium substrates by too much organic matter which in turn produces H2S. Keep this orgainic level down and you should avoid these conditions. Nothing to do with substrate heaters. For instance my substrate of silica sand has been in place nearly four years now and I've never had any anaerobic problems. Having loads of rooted plants most likely helps though. When I've done a rescape I normally dig my hand in the substrate so my fingers touch the bottom to check for any problems and so far none found. My views on a good substrate to avoid anaerobic conditions is to use a good grain size (approx 3mm) and prevent too much organic build up. Having this provides plenty of water circulation through the substrate.

    Take a look at Jeff Walmsley's tanks where he uses substrate heating and gets really nasty anaerobic patches in his substrate. Think it was in PFK a while back where he even had some lovely photo's of this.

    On the earth is flat theory the reason you see the top the ship first is due to the temperature difference of the water and the air. This causes light to bend very slightly where water and air are in contact with each other, which over a very large distance can cause you only to see the top of the boat. This you see proves that the earth is flat ;)

    James
     
  16. Ed Seeley

    Ed Seeley Member

    Messages:
    3,262
    Location:
    Nottingham
    Lol! :lol:
     
  17. sks

    sks Guest

    I can say with experience that using a heating cable it does not actually do anything, and I've had a few in my time. It was only readiing Barr's comments and experiences that I soon realized what I was doing: listening blindly to Dennerle all these years. I've been through 4 heating cable now (and the Dennerle ones do FAIL on you after some time), with the present one switched off.

    I've had a long conversation with a LFS owner in Dartford who I will not name, but he seems obsessed with Dennerle and doesn't want to deviate from the use of heating cables, and will not listen/accept current findings advances. I suppose he has vested interests since he stocks their products, but I think we have moved on. It pays to do your homework sometimes.
     

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