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Confusion about EI and other myths

Discussion in 'Estimative Index' started by Tom Barr, Oct 21, 2008.

  1. Gerryd

    Gerryd Plant Guru Team
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    Dave,

    Please note that liquid ferts are mostly water with some ferts added. Dry ferts are much cheaper and much more concentrated. You may have to really dose retail ferts to get the same affect as dry ferts.

    A lb of kn03 is pretty cheap in the long run...
     
  2. Tug

    Tug Lifetime Charter Member
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    Dave,
    You are talking about two different things. For example, a daily dose using dry KNO3 for your tank would be about 1/16 tsp or about 3.9ppm. To get that same ppm from, lets call it SeaChem Nitrogen, you would dose about 3ml or a little over 1/2tsp ever day.
     
    #42 Tug, Mar 26, 2010
    Last edited by a moderator: Mar 26, 2010
  3. daversa

    daversa Junior Poster

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    Thanks for the info guys, this helps a lot. I think I'll pick up some dry ferts for home and just try out the liquid stuff at work where it's pretty easy to dose daily. I just need to get my c02 knowledge down and I think I'm ready to start on my home tank :)
     
  4. mbtshoes2011

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    I have seen CO2 cause twisting in a dozen or more species while leaving other species unaffected. I added a bit more CO2, the issue went away, the dosing was EI and the dosing was consistent the entire time. I've done perhaps 30 times over the years now.
     
  5. Tom Barr

    Tom Barr Founder
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    So have I:)

    But even when you tell others, they often do not believe it, adjusting CO2 for many.... is bedeviling.
    Not easy to convince people. Easy if you have seen it and done, but if not??? Much harder to accept.


    Regards,
    Tom Barr
     
  6. yme

    yme Lifetime Charter Member
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    yep! you nail it.

    I think the biggest problem is that people cannot keep (difficult) plants healthy in general.
    And if you fail even when you increase co2 to the point where shrimps are dying, it is hard to accept that co2 is the culprit...
    been there.... and actually I am still at that point :)

    greets,

    yme
     
  7. ismenio

    ismenio Lifetime Members
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    Well, we got a problem, if we have to increase the CO2 so much to get rid of algae with some shrimps dying, well, you know what i mean, plants our fish ? Chose one.
    I don´t think is a good choice sinserely.

    Regards
     
  8. Tom Barr

    Tom Barr Founder
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    I think it helps if you have multiple aquariums also.
    I've had one tank that was pesky, but the other 2-7 aquariums where fine and dosed similar amounts, same sediments, light intensity etc.

    It really can tick you off.
    But as long as you can rule out a few of the things..........then you can get somewhere and get closer to resolving the root of the problem.

    A few give up and go back to nutrients, nothing wrong with that either.....but we learn less and cannot say what else is going on, what is the root issue nor explain why others do not have such issues when the nutrients are high PPM's.
    So it shows we have some area for improvement in our horticulture skills on the one pesky tank, or maybe you are unlucky enough to have more than one?
    haha

    hopefully not.

    Regards,
    Tom Barr
     
  9. Tom Barr

    Tom Barr Founder
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    I agree, the primary safety is always to the livestock.
    Plants and algae can be addressed with far more patience and worries. They can always be brought back or beaten down in the case of the algae at sometime in the future.

    But if we look at the whole picture........what drives CO2 demand? Are some plants better at competing for lower ranges of CO2 than say another plant species?
    Light drives CO2 demand, so with less intensity, we have less demand and easier management.

    That helps.
    Then the respiration issue is a ratio of CO2 and O2. So good O2, current, some surface flow is a wise idea.
    I have a lot more fish than most aquarist do in their fully CO2 enriched aquariums.

    I waste some CO2 ensuring more O2, but it's not much really, same is true for the nutrients, I make sure I have plenty.
    I am a miser when it comes to the lights however.

    We can also adjust the CO2 very slow and carefully.
    Monitoring O2 is also a wise idea if you want to know the tolerances of fish, you MUST HVAE BOTH good measure of O2 and CO2 to do this correctly in terms of stress for a particular fish or shrimp.

    40ppm of CO2 might be fine for my client's tank with discus, another tank with less turn over, flow/filtration etc? Maybe only 20ppm.
    If they also have higher light than my client's?
    They will have troubles.

    So light and O2 also can play a big role.
    But we can hedge things so there's less risk to fish/shrimp and the likelihood of algae with less light.
    That is the take home message really.

    Even if you chose to use PO4 limitation on top of this, then usign less light will make this all that much easier to do and manage.
    Regardless of the method chosen, less light should help in all cases. Oly where the loading rate is higher than the plants can remove will it be an issue, or where the tap water is loaded etc.

    Regards,
    Tom Barr
     
  10. ismenio

    ismenio Lifetime Members
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    Sorry Tom but i don´t have understand one thing.
    The nutrients N P K Fe and others not affect the fishs but the co2 can kill them, what is the limit for co2 ?
    And if we can not increase more the co2 because the fish? Decrease the light ? Nothing more to do i think.

    Regrads
     
  11. yme

    yme Lifetime Charter Member
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    I totally agree. I made a mistake and am fully responsible. lifestock is of course way more important.
    Saying this... if one get's the advice to increase co2 levels... and increase even more if plans are still stunting... people will push things too hard and shrimps will die. I am sure that I am not the only one who made this mistake.
    What I do realize now, is that with more surface agitation you can get away with more co2. (thumbs up for the vortech!!!)

    I do not only think it, I know it :) It is pretty hard to do statistics on n=1


    I don't know, but in about 6 really amazing tanks I measured around 50 mg/l.
     
  12. ismenio

    ismenio Lifetime Members
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    Thanks Tom , sorry the second post but i didn´t see your answer when i have post.
    Thanks to Yme.
    If we can´t increase the co2 we must decrease the light since the problem in most cases is low co2 for the light we have.

    Regards
     
  13. yme

    yme Lifetime Charter Member
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    @ismenio:

    indeed! and, although it is just my experience, I think that a good current and surface agitation is very, very important.
    Just saying: increase your co2 level is just not enough, it is a bit more complicated.

    greets,

    yme
     
  14. Tom Barr

    Tom Barr Founder
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    Measuring O2 + CO2 at the same time and over the entire day cycle is not easy.............but.for light and nutrients?
    They are extremely easy.

    Makes a big difference.

    Regards,
    Tom Barr
     
  15. Tom Barr

    Tom Barr Founder
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    YME suggested a range in the 50ppm or so.
    I have gone to 80ppm for some tanks, others in the 40-60ppm range.
    I have high current though and highly stocked fish tanks.

    So the O2 is 7-10ppm as well.

    I think each species will have a limit of O2/CO2 ratios, both mst be measured to test the limits of the species of fish in question.

    Plecos, Discus etc are more sensitive, or highly active fish that are larger.
    Tetras and the typical shrimp/fish we see in nice pretty aquascapes (top winning in ADA's contest say) are really bullet proof, easily handling 80ppm or more ppm.

    It's rare to see anything but in such contest.

    Regards,
    Tom Barr
     
  16. srozell

    srozell Guru Class Expert

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    I find this comment interesting, perhaps you can elaborate on it.

    Testing calcium and finding levels at 5ppm, while low, would indicate to me that there is still calcium available to the plants. I don't know how much calcium has to be in the water or substrate to continue to support plant growth (especially not knowing what else was limited in the tank). Perhaps you can elaborate on this.
     
  17. Tom Barr

    Tom Barr Founder
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    Most nicer tanks sit about here at 40-60ppm IME. My 180 is up to 70-80ppm during the day.
    I know you are one of the few that have the CO2 meter though.

    I installed 2 of them this weekend.
    I had to rewire the coaxil redox cables to accept the 2 leads from the Oxyguard.
    This way we can correlate, data log and control CO2 ppm via the controlled Redox function.

    Not an easy fix.

    But.....it allows me polenty of play time with these things and I made 4 different methods to confirm that the readings where indeed accurate:

    Sealed chambers and allowing the gas to settle inside and partial pressure law.
    25% CO2:N2 mix vs a 100% CO2 gas.
    Ultra pure water and a known KH buffer and then pH/KH scaling.
    Oxyguard's calibration method(which did not do well vs the other 3 methods listed above).

    The client's tank was CO2 limited, and within a min I knew it was, even though the CO2 read 40ppm, it had not been calibrated for almost 2 years.
    It read 40ppm when it was really under 20ppm. The new meter and the claibration slope fixed this right up.

    So even for me, the $$$ spent, the time, CO2 is a mofro bugger.

    It'll burn any and everyone.
    If not today, just you wait.
     
  18. Tom Barr

    Tom Barr Founder
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    Yes, it is low, but few folks have tap less than this and we add Ca from many other sources as well.
    If you used ultra pure water, or all RO water etc, and plain sand, no ADA AS or garden soils etc, dolomite, onyx sand etc etc.....
    Then you do not do many water changes........

    Now you might end up with an issue.
    I've seen some very supper low Ca++ water in natural system and saw no evidence of any Ca++ issues.

    I think the point is that while possible in aquariums, it would be something that hobbyist would have to go out of their way really hard to do.
    CO2, on the other hand,........ is bugger of 7 th degree.

    You are correct, 5ppm is still not limiting, but there might be several uptake enzymatic mechanisms that require say 1 ppm, 3ppm and 5ppm, anything above 5 will not change the uptake demand.
    This is true for K+, NO3 etc....... and it would not be unreasonable to assume the same is true for Ca++.

    CO2 can be used to illustrate this issue as well, while in theory, 3 ppm is non limiting as logn as it is resupplied rapidly.........we know plants do not grow at non limiting levels till we hit about 40-50ppm for many species.
    So concentration does indeed drive uptake.

    I should have seen some limitation at 5ppm for the claims to be correct, I tried to go out of my way for Ca++, I've yet to be able to do it, even with soft Sierra snow melt water with low KH and GH(1 and 2 respectively)
    So there's more that we really do not know here, but CO2 seems to be much more likely, not Ca++.

    Most of the Ca++ evidence comes from terrestrial plants, which we know are not CO2 limited like aquatics and the measurement and mainteance of CO2 is far easier.
    So that reference for Ca++ is a poor comparison.
     
  19. yme

    yme Lifetime Charter Member
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    hi!

    this concerns me!!

    What would you advice me to do?
    I calibrate once every 2-3 months or so. I find never a big difference between before and after calibration. 5 ppm at most.


    I don't have N2 at home, so this method is not an option.

    The pH/KH scaling seems most feasible to me.
    However, how can I do this in practice?
    Making the KH-solution is of course no problem.
    But how can I add CO2 , mix it using a stirring bar and measure both CO2 and pH at the same time? (and don't make errors due to the slow respond time of the CO2-probe)
    I don't really see yet the setup of this method.

    thanks!

    yme
     
  20. Tom Barr

    Tom Barr Founder
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    Well, after looking at it, they also have issues with this also.
    It's not easy for them to offer a user freindly method.

    So I understand.

    I tried 3 different methods to verify, not satifisied with their method for calibration myself.

    If you can construct a nice large drop checker and can withdraw a smaple with a suction bulb, and have areference KH solution and a pH probe calibrated well in this water, and sealed, you can allow for a long time to pass and equilibrate.
    Unlike a drop checker 2 huge trade offs, the time delay and the poor accuracy of pH, this is over come.

    The reference solution is all pure water and sodium carbonate reference solution.

    Since time in not really important for calibration, this can be allowed to equilibrate for 24-48 hours etc.
    Then take a highly accurate pH reading.

    This reading can then be used to adjust the slope of the CO2 meter.
    You may/should also vary the CO2 content for the sample test water.
    So try to test a low(no CO2 added), then med, say 30ppm and then say 60ppm.

    Compare this reading to the tank's pH and KH reading, see if they match.
    If so, you have few interefearing KH factors and can use the pH/KH relationship.
    That was the case here, since they change water very often and use RO/blended with a little tap.

    You can make these chambers out of acrylic, then add a rubber grommett for the pH and then another for the CO2 probe.
    I think it would be even better to allow plenty of time, but add CO2 gas to the air in the dry part of the chamber to change the concentration vs the way I did it, which was a PITA.

    Still, with a known KH and a pH meter, we should if the water is oure and only HCO3..be able to dial in a reference CO2 ppm to 1ppm or less perhaps.

    There's another company that makes CO2 systems for ultra pure water, they go to the ppb range they say, seeign their claibration methods might be interesting, still, I like the IR for gas, then convert that from the seal chambers to ppm for aquaous solutions for the gas in the head space.
     
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