Substrate nutrients and EI dosing

Discussion in 'Substrates' started by Mortis, 8 Sep 2009.

  1. Mortis

    Mortis Member

    Messages:
    355
    Just wondering, what kind of a substrate goes well with EI dosing ? What I meant is what kind of nutrients does the substrate need to have when paired with EI dosing ? Obviously and inert substrate is not ideal for a planted aquarium but other than that how fertile should the substrate be ?
     
  2. ceg4048

    ceg4048 Expert/Global Moderator Staff Member

    Messages:
    8,952
    Location:
    Chicago, USA
    Hi,
    You should not think of substrate and water column in the same way one thinks about matching one's shoes with a pair of pants. So there's no matching or pairing in this sense.The same nutrients that are in sediment are also in EI. Plants uptake whatever nutrients they can from any source or location they can. Ideally, a nutrient rich substrate should be combined with EI dosing which will mean that nutrient uptake will occur from both locations. This is not gospel however, because one can have equal success using a completely inert substrate such as aquarium gravel or sand. As long as nutrients are available in the water column, there is much less urgency to have a nutritious substrate. A nutritious substrate is handy for example, when one leaves town and is not available to dose the water column for a few days. Nutritious substrates are also very expensive and the marketing departments work overtime trying to convince you to part with your hard earned cash in exchange for these "indispensable" substrates. The reality is that these are really mostly luxuries. Look in the Substrate Section and check what JamesC has been able to do with a common clay product called Akadama.

    Cheers,
     
  3. Mortis

    Mortis Member

    Messages:
    355
    Got it, need to have atleast some nutrients in the substrate. I guess it depends more on the plants as well right ? Heavy root feeders and most carpet/foreground plants do well in a nutritious substrate.

    Im setting up a tank at my parents place in India right now and while you do get ADA and Ferka substrates they are quite pricey and hard to get. Instead Im going to use what is known here as "river sand". It is a dirt cheap (lol) easily available substrate and I have seen some decent planted tanks set up using it.

    It is basicaly fine brown gravel, about 2-4 mm in size with Laterite material mixed in. I would say the ratio between the intert (might not be) gravel and laterite is about 60 : 40 or 70 : 30. It is mainly rich in iron and has some micronutrients as well as organic matter so it should be wel balanced.

    Just wondering what thoughts are on laterite as a substrate, especially in this case where it is mixed evenly throughout the gravel and not used as a base layer. Will it cause a lot of algae ?
     
  4. ceg4048

    ceg4048 Expert/Global Moderator Staff Member

    Messages:
    8,952
    Location:
    Chicago, USA
    Well, perhaps I was a bit unclear. You don't "need" a nutritious substrate or even a minimal level of nutrients if you are dosing EI. It's simply that having nutrients in the substrate is better than not having nutrients in the substrate. This is like 4 meals a day being better for weight gain than 3 meals a day, but you don't really "need" 4 meals a day, do you?

    Some people are against dosing the water column, or prefer not to dose the water as richly as EI allows. If you are dosing on the lean side, or if you are inconsistent with your water column dosing then it's a good idea to have a nutritious substrate. The criticality depends on the environmental conditions that you set in the tank. If your lighting is very high and your CO2 is high, or if your water flow and distribution is marginal then there is a greater likelihood that nutrients in the substrate will be helpful.

    In my opinion the concept of heavy root feeding is a myth. Crypts, Swords and other so called heavy root feeders gain just as much from water column dosing as other plants. In fact, a large sword will strip your tank water of it's nutrients in a hurry. Their leaves have massive surface areas which they use to great advantage. There are one or two very good reasons for having a large root structure besides root feeding, and I think people forget about that. A similar story is found with carpet plants. If a nutritious substrate is available they will take advantage, however they feed from their leaves just as any other aquatic.

    River sand will work fine, especially if it's rich in silt. If the river is fast flowing then much of the nutrients get wash away, but in slow flowing rivers the silt falls out of suspension and enriches the sediment. There are some lake sediments which massively outperform AS as a direct result of their accumulated organic silt.

    Laterite used to be considered THE sediment material due it's supposed high iron content, however experience has shown that it's severely overrated. Iron is a trace element. There is a reason these are called "Trace" and "Micro"nutrients, that being that the plant doesn't really need much of them so all the hysteria about laterite and it's iron content is completely overblown. The fact that laterite is a clay product is actually much more relevant. :shh: A fact overlooked by so many. Clay has one of the highest Cation Exchange Capacities (CEC) of all sediment materials. CEC allows the sediment material to attract and to hold positively charged nutrient ions which can then be passed on to the plant roots. This is much more valuable attribute than just having iron, because it means that the sediment particles continually can pull nutrients from the water and transport them to the root hairs. Sediments having high clay content therefore is all goodness from that perspective, but you'd do well to forget about all that hoopla about iron. Dose your trace element mix as normal and focus on delivering the macronutrients N, P and K to the plant leaves. That's where you'll make hay. :idea:

    Neither laterite nor nutrients can cause algae, so rest assured. ;)

    Cheers,
     
  5. Mortis

    Mortis Member

    Messages:
    355
    Good information and advice. I was leaning towards a nutrient substrate because this tank will have a lot of foreground plants like hairgrass. My theory is that when the hairgrass starts browning and switching from emmersed to submerged form, the leaves wont do as good a job of absorbing nutrients, however the root system will be intact and can uptake nutrients, ensuring faster recovery/growth. Does this make sense ?

    Thinking about it, a lot of commercial substrates and abse layers have a lot of clay in them such as JBL, Ferka, etc. I remembered reading about the usefulness of clay in the substrate. Thanks for reminding me.

    Surprisingly, I have rarely had algae in any of the tanks I have set up in India. Other than a bit of thread algae or whatever the softer version of hair algae is, I havent had anything. It was easily cleared up by shrimp in a couple of days.

    In fact, once when I was trying to make green waterto grow fairy shrimp, I found it impossible to do so ! I kept the tank next to an east facing window AND had lights on above it for 18 hrs a day. I even added craploads of ferts, a handful of mud, ammonia. Nothing worked.

    So yeah, I definitely agree that excess ferts do not cause algae !
     
  6. ceg4048

    ceg4048 Expert/Global Moderator Staff Member

    Messages:
    8,952
    Location:
    Chicago, USA
    Hi,
    Yes your logic is sound, and getting the plants off to good start during the transition is a fair goal. This is why ADA have the many enriched sediments supplements like Powersand and so forth. In practice though, as long as the water column is enriched and CO2 is adequate the transition phase is not too bad. Again, you can pay the exorbitant price of these products, or you could save money and just have a bit more patience. ;)

    Thread algae is a CO2 issue. Many people focus so much on sediment enrichment that they forget that almost all the issues are CO2 related. :idea:

    Cheers,
     
  7. Mortis

    Mortis Member

    Messages:
    355
    Yup, it was most definitely a CO2 issue. DIY CO2 didnt work on one of those tanks an on the other I was only dosing Excel, cant remember but I think I was dosing low or on alternate days So yeah, definitely a CO2 issue with those tanks. This time around I going to use both DIY Co2 and Excel. It will also be my first tank with EI dosing. Hopefully it will turn out the way I want it to.
    Im also slowly getting stuff together for a larger tank which will have pressurised CO2. When I do this, Ill switch the smaller tank to pressurised as well.

    Only thing to worry about is scaping and getting the perfect rocks and wood :)
     

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