Aquatic Plant Science

The science of submerged aquatic plants in the aquarium hobby


    Heavy metal adsorbent materials

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    Lawrence So

    Posts : 21
    Join date : 2016-07-20
    Location : San Francisco, CA

    Heavy metal adsorbent materials

    Post by Lawrence So on Thu Jul 21, 2016 10:32 am

    Since high concentrations of certain heavy metals like copper are likely causing issues with plant health, and copper tends to be very high straight from tap water, I've been looking for ways to remove them from the water column.

    I've found that Seachem sells a synthetic copper and heavy metal adsorbent called Cuprisorb.  100mL cost $10+.  But from further research, there may be much cheaper alternatives.

    Vermiculite, often used as a soil amendment and can easily be found at any garden supply store, is capable of adsorbing copper and other heavy metals.  It's also used in wastewater cleanup.  It's also really cheap.

    I've placed some vermiculite inside a nylon stocking, soaked and rinsed it clean, and put it into my canister filter a couple of days ago.

    Within just two days, I observed that Ammannia pedicellata "Golden" grew the most normal leaves it's ever grown before. They look healthy with no wrinkles.  The fact that they are even growing is amazing!  Rotala "H'ra" also turned a shade of red that I've only seen at Aqua Forest Aquarium tanks.

    [You must be registered and logged in to see this image.]
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    It's too soon to conclude that vermiculite is responsible for these observations or if it's from the lack of trace dosing but I'm optimistic.

    Positron

    Posts : 3
    Join date : 2016-07-21

    Re: Heavy metal adsorbent materials

    Post by Positron on Mon Jul 25, 2016 10:34 am

    I've used cuprisorb by seachem before. It's extremely proficient at savaging heavy metals from the water. In my opinion a bit too good because there was little left for plants. I"ve found the best way to taking metals out of the water is by use of giant duck weed.

    It's also a good indicator of what's going on in the tank.

    I've never kept Ammannia before, but I think what is happening there is there was an excess of some micro...probably Fe or Mn causing issues. Decreasing both of these put that ratio in a better spot....now i'm seeing Fe deficiency issues? Total white new growth? Hmmm

    When using micro ferts in a setup with something that takes them out (vermiculite), I can only venture a guess that your going to run into tox issues depending on what the vermiculite removes better. If it removes more Mn, then Fe will become an issue. Also, with working with very small amounts of traces (which is fine), throwing off the ratios are much, much easier.

    I wonder how this plant would respond to dosing a small amount of iron gluc? (don't use chelate complexes like DTPA)?

    Lawrence So

    Posts : 21
    Join date : 2016-07-20
    Location : San Francisco, CA

    Re: Heavy metal adsorbent materials

    Post by Lawrence So on Mon Jul 25, 2016 2:31 pm

    Thanks for sharing your experiences on Cuprisorb.

    Does the Ammannia look white in the picture? It's actually a light yellow, IRL.  Ive just added minute amount of Fe sulfate to see if there are any effects.

    What I've observed with dosing Microplex is that even at <0.004mg/L of Fe, I get tox symptoms: leaves start to crumple.  In Rotala rotundifolia "H'ra", loss of pigment occurs as seen on the bottom part of the picture:
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    It's very strange.  It could be the copper, or worse, the EDTA chelator itself.

    Vermiculite has higher affinity to Cu, then Zn, so it should remove more copper before the other metals.  I'll need to find out it's iron and manganese adsorption abilities.

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    Re: Heavy metal adsorbent materials

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