self made root fert

Discussion in 'Aquarium Fert Dosing' started by tanker, 30 Oct 2008.

  1. tanker

    tanker Member

    Hi people...
    i've read the discussion on water column dosing vs substrate dosing. But i'm just curious what difference would it make.

    therefore i've bought some empty capsules and stuffed some KNO3 and KH2PO4 in, and then inserted it in a small portion of my tank with hair grass... (foreground, left)

    actually something is strange in my aquarium as the half left portion of the hair grass is growing too slowly, some not green, while the half right side is taking off nicely, growing more compact each day. it is a 1.5ft small tank, and diffuser is at the left side. light is even on the left and right, HOB at the left, thus blowing the CO2 bubbles down at the left front side first. so logically the left part should grow better. So i'm trying to see if some localised substrate boost will help... (if the whole patch looks bad, i would have add more ferts into the water as a whole)

    i just got my dry ferts (KNO3, KH2PO4), and have not yet have a consistent dosing regiment. I'm throwing in small pinch of the ferts every 2 or 3 days. Generally there is no algae problem except the tiny green spot that i have on the glass.
    Any comments on the experiment?
  2. vauxhallmark

    vauxhallmark Member

    Interesting, love to hear how it goes. Have you taken a 'before' picture? You can't overestimate the usefulness of doing that!

    Hope it grows well for you,

  3. ceg4048

    ceg4048 Expert/Global Moderator Staff Member

    Chicago, USA
    Hi tanker,
    While I get what you're trying accomplish, i.e trying to determine if sediment feeding can compensate for poor water column distribution, there are nevertheless logical flaws with how you plan to do it. Here are a couple of inconsistencies you may wish to consider:

    1. Whatever results you obtain or conclusion you draw will be invalid because you have yet to determine whether in fact localized water column KNO3/KH2PO4 shortage is occurring on the left side and whether this shortage is the cause of the browning. What if the browning is caused by localized CO2 shortage? Adding NO3/PO4 to a CO2 shortage area cannot compensate for lack of CO2. So if the plants on the left side suddenly start turning green this tells you nothing especially since the plants on the right side are healthy with no additional sediment supplements.

    2. If this is a flow problem you would best be served by moving the equipment to the mirror image side of the tank so that the flow problem would be transferred to the green side. If you then saw a reduction of growth and browning of the right side while simultaneously seeing an improvement on the left side this would demonstrate a much better correlation of a water column issue.

    3. Fundamentally, you must be able to grow the plants successfully before attempting any kind of diversion or experimentation otherwise you will not be able to logically attribute causal factors to a change without knowing why there was a problem in the first place. In fact it would be more logical to place the root tabs in sections of the RH side substrate because this side is behaving normally. You could then determine after a few weeks whether there was a difference in the section of the right side which had the tabs in place. In this way you have a control. Again, experimenting on an area which has mysterious behavior makes it impossible to rationalize the results.

    4. If you really want to see the difference between one method and another then you need several tanks half of which are water column dosed and the other half of which is sediment dosed. The more tanks you have in the experiment the more statistically relevant the results will be. Keep as many things consistent between the two tank groups as possible and measure the results after the test period. Measure root mass, stem mass and total mass and compare.

    In any case I don't see why there has to be an argument for one versus another. Use both simultaneously because that's what plants do. They feed from any location they can. Using both a nutritious substrate as well as dosing the water column provides the best of both worlds so there is no need for factional strategies. If I can't afford to buy rich substrates then I know that water column dosing can take me where I want to go. This is not really a big deal. The extremist faction which swear by exclusive sediment dosing (and decry water column dosing) do so because they believe that nutrients in the water column cause algae. I've seen all kinds of algae and growth problems (as well as successes) in each type of tank, regardless of faction, so I already have migrated to the opinion that doing both is best but doing either exclusively can also work as long as the tank parameters do not stray out of the proper "envelope".

  4. tanker

    tanker Member

    Alright, great. this teaches me sth about experimenting. right now i only have 1 tank, i'll get another in the future but cant afford to have too many for experimenting purposes... (unfortunately)

    i will soon insert more tabs in the right section, as suggested to see if they have supergrowth :D should be in a week or 2 time and only a small section, say 2" X 2" i'm concerned that the ferts could be released into the water too quickly and make the water too salty? as these are very soluble ferts and my tank is small...

    i dont think the section has CO2 shortage as the CO2 bubbles reach there first. i've tried the opposite direction previously (before the hairgrass), and no notable difference in plant growth

    i've read that HOB causes inefficient CO2 in the water? but i think this should not be significant...

    i'm still in the 'learning how to grow properly' stage, so bear with me ppl :D

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